diff --git a/annif/cli.py b/annif/cli.py
index 82f2835a..f11b019c 100644
--- a/annif/cli.py
+++ b/annif/cli.py
@@ -633,9 +633,9 @@ def run_upload(
     that match the given `project_ids_pattern` to archive files, and uploads the
     archives along with the project configurations to the specified Hugging Face
     Hub repository. An authentication token and commit message can be given with
-    options. If the README.md does not exist in the repository it is created with
-    default contents and metadata of the uploaded projects, if it exists, its
-    metadata are updated as necessary.
+    options. If the README.md does not exist in the repository it is
+    created with default contents and metadata of the uploaded projects, if it exists,
+    its metadata are updated as necessary.
     """
     from huggingface_hub import HfApi
     from huggingface_hub.utils import HfHubHTTPError, HFValidationError
@@ -692,8 +692,14 @@ def run_upload(
     is_flag=True,
     help="Replace an existing project/vocabulary/config with the downloaded one",
 )
+@click.option(
+    "--trust-repo",
+    default=False,
+    is_flag=True,
+    help="Allow download from the repository even when it has no entries in the cache",
+)
 @cli_util.common_options
-def run_download(project_ids_pattern, repo_id, token, revision, force):
+def run_download(project_ids_pattern, repo_id, token, revision, force, trust_repo):
     """
     Download selected projects and their vocabularies from a Hugging Face Hub
     repository.
@@ -702,10 +708,14 @@ def run_download(project_ids_pattern, repo_id, token, revision, force):
     configuration files of the projects that match the given
     `project_ids_pattern` from the specified Hugging Face Hub repository and
     unzips the archives to `data/` directory and places the configuration files
-    to `projects.d/` directory. An authentication token and revision can
-    be given with options.
+    to `projects.d/` directory. An authentication token and revision can be given with
+    options. If the repository hasn’t been used for downloads previously
+    (i.e., it doesn’t appear in the Hugging Face Hub cache on local system), the
+    `--trust-repo` option needs to be used.
     """
 
+    hfh_util.check_is_download_allowed(trust_repo, repo_id)
+
     project_ids = hfh_util.get_matching_project_ids_from_hf_hub(
         project_ids_pattern, repo_id, token, revision
     )
diff --git a/annif/hfh_util.py b/annif/hfh_util.py
index a99050be..7249bd82 100644
--- a/annif/hfh_util.py
+++ b/annif/hfh_util.py
@@ -24,6 +24,35 @@
 logger = annif.logger
 
 
+def check_is_download_allowed(trust_repo, repo_id):
+    """Check if downloading from the specified repository is allowed based on the trust
+    option and cache status."""
+    if trust_repo:
+        logger.warning(
+            f'Download allowed from "{repo_id}" because "--trust-repo" flag is used.'
+        )
+        return
+    if _is_repo_in_cache(repo_id):
+        logger.debug(
+            f'Download allowed from "{repo_id}" because repo is already in cache.'
+        )
+        return
+    raise OperationFailedException(
+        f'Cannot download projects from untrusted repo "{repo_id}"'
+    )
+
+
+def _is_repo_in_cache(repo_id):
+    from huggingface_hub import CacheNotFound, scan_cache_dir
+
+    try:
+        cache = scan_cache_dir()
+    except CacheNotFound as err:
+        logger.debug(str(err) + "\nNo HFH cache found.")
+        return False
+    return repo_id in [info.repo_id for info in cache.repos]
+
+
 def get_matching_projects(pattern: str) -> list[AnnifProject]:
     """
     Get projects that match the given pattern.
diff --git a/tests/test_cli.py b/tests/test_cli.py
index 98b6f26a..5690be48 100644
--- a/tests/test_cli.py
+++ b/tests/test_cli.py
@@ -1149,10 +1149,30 @@ def test_upload_nonexistent_repo():
     assert "Repository Not Found for url:" in failed_result.output
 
 
+@mock.patch("annif.hfh_util._is_repo_in_cache", return_value=False)
+def test_download_not_allowed_default(mock_is_repo_in_cache):
+    # Default of --trust-repo is False
+    failed_result = runner.invoke(
+        annif.cli.cli,
+        [
+            "download",
+            "dummy-fi",
+            "dummy-repo",
+        ],
+    )
+    assert failed_result.exception
+    assert failed_result.exit_code != 0
+    assert (
+        'Cannot download projects from untrusted repo "dummy-repo"'
+        in failed_result.output
+    )
+
+
 def hf_hub_download_mock_side_effect(filename, repo_id, token, revision):
     return "tests/huggingface-cache/" + filename  # Mocks the downloaded file paths
 
 
+@mock.patch("annif.hfh_util.check_is_download_allowed", return_value=True)
 @mock.patch(
     "huggingface_hub.list_repo_files",
     return_value=[  # Mocks the filenames in repo
@@ -1170,7 +1190,11 @@ def hf_hub_download_mock_side_effect(filename, repo_id, token, revision):
 )
 @mock.patch("annif.hfh_util.copy_project_config")
 def test_download_dummy_fi(
-    copy_project_config, hf_hub_download, list_repo_files, testdatadir
+    copy_project_config,
+    hf_hub_download,
+    list_repo_files,
+    check_is_download_allowed,
+    testdatadir,
 ):
     result = runner.invoke(
         annif.cli.cli,
@@ -1211,6 +1235,7 @@ def test_download_dummy_fi(
     ]
 
 
+@mock.patch("annif.hfh_util.check_is_download_allowed", return_value=True)
 @mock.patch(
     "huggingface_hub.list_repo_files",
     return_value=[  # Mock filenames in repo
@@ -1228,7 +1253,11 @@ def test_download_dummy_fi(
 )
 @mock.patch("annif.hfh_util.copy_project_config")
 def test_download_dummy_fi_and_en(
-    copy_project_config, hf_hub_download, list_repo_files, testdatadir
+    copy_project_config,
+    hf_hub_download,
+    list_repo_files,
+    check_is_download_allowed,
+    testdatadir,
 ):
     result = runner.invoke(
         annif.cli.cli,
@@ -1285,6 +1314,7 @@ def test_download_dummy_fi_and_en(
     ]
 
 
+@mock.patch("annif.hfh_util.check_is_download_allowed", return_value=True)
 @mock.patch(
     "huggingface_hub.list_repo_files",
     side_effect=HFValidationError,
@@ -1293,8 +1323,7 @@ def test_download_dummy_fi_and_en(
     "huggingface_hub.hf_hub_download",
 )
 def test_download_list_repo_files_failed(
-    hf_hub_download,
-    list_repo_files,
+    hf_hub_download, list_repo_files, check_is_download_allowed
 ):
     failed_result = runner.invoke(
         annif.cli.cli,
@@ -1311,6 +1340,7 @@ def test_download_list_repo_files_failed(
     assert not hf_hub_download.called
 
 
+@mock.patch("annif.hfh_util.check_is_download_allowed", return_value=True)
 @mock.patch(
     "huggingface_hub.list_repo_files",
     return_value=[  # Mock filenames in repo
@@ -1326,6 +1356,7 @@ def test_download_list_repo_files_failed(
 def test_download_hf_hub_download_failed(
     hf_hub_download,
     list_repo_files,
+    check_is_download_allowed,
 ):
     failed_result = runner.invoke(
         annif.cli.cli,
diff --git a/tests/test_hfh_util.py b/tests/test_hfh_util.py
index 6b5f3774..0bc22021 100644
--- a/tests/test_hfh_util.py
+++ b/tests/test_hfh_util.py
@@ -1,16 +1,60 @@
 """Unit test module for Hugging Face Hub utilities."""
 
 import io
+import logging
 import os.path
 import zipfile
 from datetime import datetime, timezone
 from unittest import mock
 
 import huggingface_hub
+import pytest
 from huggingface_hub.utils import EntryNotFoundError
 
 import annif.hfh_util
 from annif.config import AnnifConfigCFG
+from annif.exception import OperationFailedException
+
+
+@mock.patch("annif.hfh_util._is_repo_in_cache", return_value=False)
+def test_download_allowed_trust_repo(mock_is_repo_in_cache, caplog):
+    trust_repo = True
+    repo_id = "dummy-repo"
+
+    with caplog.at_level(logging.WARNING, logger="annif"):
+        annif.hfh_util.check_is_download_allowed(trust_repo, repo_id)
+    assert (
+        'Download allowed from "dummy-repo" because "--trust-repo" flag is used.'
+        in caplog.text
+    )
+
+
+@mock.patch("annif.hfh_util._is_repo_in_cache", return_value=True)
+def test_download_allowed_repo_in_cache(mock_is_repo_in_cache, caplog):
+    trust_repo = False
+    repo_id = "dummy-repo"
+
+    with caplog.at_level(logging.DEBUG, logger="annif"):
+        annif.hfh_util.check_is_download_allowed(trust_repo, repo_id)
+    assert (
+        'Download allowed from "dummy-repo" because repo is already in cache.'
+        in caplog.text
+    )
+
+
+@mock.patch("huggingface_hub.utils._cache_manager.HFCacheInfo")
+@mock.patch("huggingface_hub.scan_cache_dir")  # Bypass CacheNotFound on CI/CD
+def test_download_not_allowed(mock_scan_cache_dir, mock_HFCacheInfo):
+    trust_repo = False
+    repo_id = "dummy-repo"
+    mock_HFCacheInfo.return_value.repos = frozenset()
+
+    with pytest.raises(OperationFailedException) as excinfo:
+        annif.hfh_util.check_is_download_allowed(trust_repo, repo_id)
+    assert (
+        str(excinfo.value)
+        == 'Cannot download projects from untrusted repo "dummy-repo"'
+    )
 
 
 def test_archive_dir(testdatadir):