diff --git a/tools/internal_ci/linux/grpc_interop_matrix.cfg b/tools/internal_ci/linux/grpc_interop_matrix.cfg
index 7178d83e2c5..ae59e930f77 100644
--- a/tools/internal_ci/linux/grpc_interop_matrix.cfg
+++ b/tools/internal_ci/linux/grpc_interop_matrix.cfg
@@ -16,6 +16,7 @@
 
 # Location of the continuous shell script in repository.
 build_file: "grpc/tools/internal_ci/linux/grpc_interop_matrix.sh"
+# grpc_interop tests can take 1 hours to complete.
 timeout_mins: 300
 action {
   define_artifacts {
@@ -23,8 +24,3 @@ action {
     regex: "github/grpc/reports/**"
   }
 }
-
-env_vars {
-  key: "RUN_TESTS_FLAGS"
-  value: "--language=all --release=all --allow_flakes --report_file=sponge_log.xml --bq_result_table interop_results"
-}
diff --git a/tools/internal_ci/linux/grpc_interop_matrix.sh b/tools/internal_ci/linux/grpc_interop_matrix.sh
index fea365eeff5..4c24c434883 100755
--- a/tools/internal_ci/linux/grpc_interop_matrix.sh
+++ b/tools/internal_ci/linux/grpc_interop_matrix.sh
@@ -22,4 +22,4 @@ cd $(dirname $0)/../../..
 
 source tools/internal_ci/helper_scripts/prepare_build_linux_rc
 
-tools/interop_matrix/run_interop_matrix_tests.py $RUN_TESTS_FLAGS
\ No newline at end of file
+tools/interop_matrix/run_interop_matrix_tests.py --language=all --release=all --allow_flakes --report_file=sponge_log.xml --bq_result_table interop_results $@
diff --git a/tools/internal_ci/linux/pull_request/grpc_interop_matrix_adhoc.cfg b/tools/internal_ci/linux/pull_request/grpc_interop_matrix_adhoc.cfg
deleted file mode 100644
index 6726384f188..00000000000
--- a/tools/internal_ci/linux/pull_request/grpc_interop_matrix_adhoc.cfg
+++ /dev/null
@@ -1,30 +0,0 @@
-# Copyright 2017 gRPC authors.
-#
-# Licensed under the Apache License, Version 2.0 (the "License");
-# you may not use this file except in compliance with the License.
-# You may obtain a copy of the License at
-#
-#     http://www.apache.org/licenses/LICENSE-2.0
-#
-# Unless required by applicable law or agreed to in writing, software
-# distributed under the License is distributed on an "AS IS" BASIS,
-# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-# See the License for the specific language governing permissions and
-# limitations under the License.
-
-# Config file for the internal CI (in protobuf text format)
-
-# Location of the continuous shell script in repository.
-build_file: "grpc/tools/internal_ci/linux/grpc_interop_matrix.sh"
-timeout_mins: 300
-action {
-  define_artifacts {
-    regex: "**/sponge_log.xml"
-    regex: "github/grpc/reports/**"
-  }
-}
-
-env_vars {
-  key: "RUN_TESTS_FLAGS"
-  value: "--language=all --release=all --allow_flakes --report_file=sponge_log.xml"
-}
diff --git a/tools/interop_matrix/run_interop_matrix_tests.py b/tools/interop_matrix/run_interop_matrix_tests.py
index f887bd0fdd2..9d442346a70 100755
--- a/tools/interop_matrix/run_interop_matrix_tests.py
+++ b/tools/interop_matrix/run_interop_matrix_tests.py
@@ -46,7 +46,6 @@ _RELEASES = sorted(
             for lang in client_matrix.LANG_RELEASE_MATRIX.values()
             for info in lang)))
 _TEST_TIMEOUT = 60
-_PULL_IMAGE_TIMEOUT_SECONDS = 10 * 60
 
 argp = argparse.ArgumentParser(description='Run interop tests.')
 argp.add_argument('-j', '--jobs', default=multiprocessing.cpu_count(), type=int)
@@ -210,43 +209,17 @@ def find_test_cases(lang, runtime, release, suite_name):
 _xml_report_tree = report_utils.new_junit_xml_tree()
 
 
-def pull_images_for_lang(lang, images):
-    """Pull all images for given lang from container registry."""
-    jobset.message(
-        'START', 'Downloading images for language "%s"' % lang, do_newline=True)
-    download_specs = []
-    for release, image in images:
-        spec = jobset.JobSpec(
-            cmdline=['gcloud docker -- pull %s' % image],
-            shortname='pull_image_%s' % (image),
-            timeout_seconds=_PULL_IMAGE_TIMEOUT_SECONDS,
-            shell=True)
-        download_specs.append(spec)
-    num_failures, resultset = jobset.run(
-        download_specs, newline_on_success=True, maxjobs=args.jobs)
-    if num_failures:
-        jobset.message(
-            'FAILED', 'Failed to download some images', do_newline=True)
-        return False
-    else:
-        jobset.message(
-            'SUCCESS', 'All images downloaded successfully.', do_newline=True)
-        return True
-
-
 def run_tests_for_lang(lang, runtime, images):
     """Find and run all test cases for a language.
 
   images is a list of (<release-tag>, <image-full-path>) tuple.
   """
-    # Fine to ignore return value as failure to download will result in test failure
-    # later anyway.
-    pull_images_for_lang(lang, images)
-
     total_num_failures = 0
-    for release, image in images:
+    for image_tuple in images:
+        release, image = image_tuple
         jobset.message('START', 'Testing %s' % image, do_newline=True)
-
+        # Download the docker image before running each test case.
+        subprocess.check_call(['gcloud', 'docker', '--', 'pull', image])
         suite_name = '%s__%s_%s' % (lang, runtime, release)
         job_spec_list = find_test_cases(lang, runtime, release, suite_name)