Turkish officials ordered a Syrian passenger plane that departed from Moscow to land in Ankara on Tuesday night, under the suspicion that it was carrying weapons headed for Damascus.

Foreign Minister Ahmet Davutoglu said the government received a tip that the plane might be carrying “certain equipment in breach of civil aviation rules,” but did not elaborate.

“We forced the plane to land in order to inspect its cargo,” he told Turkey’s National Television.

There were 35 people on board the A-320 plane. It was escorted to Ankara’s Esenboga Airport by Turkish F4 jets for inspection, Al-Arabiya reported. Turkish authorities have meanwhile declared Syrian airspace to be unsafe.

Both Russia and Iran are supporters of the Assad regime in Syria, and Russia has blocked the U.N. Security Council from passing effective resolutions numerous times.