An Armenian plane carrying humanitarian aid for Syria was forced to land in Turkey on Thursday for an inspection of its cargo, the Anatolia news agency reported.
The cargo plane landed at Erzurum airport in eastern Turkey where teams of police and troops with sniffer dogs began a search, it said.
It was the second time in a month that the Turkish authorities have ordered an Armenian plane heading for Syria to land for security checks.
On October 15, another Armenian plane carrying humanitarian aid to Syria's battered second city of Aleppo was forced to land at Erzurum airport but the plane was allowed to resume journey after officials said no suspect cargo turned up during searches.
Last month, Turkish jets forced a Syrian plane flying from Russia to land at Ankara airport because of what it called suspect cargo.
Turkish Prime Minister Recep Tayyip Erdogan said the cargo contained military equipment for the Syrian defence ministry, but Russia said it was dual-purpose radar equipment which was not banned by international conventions.
Former allies Turkey and Syria have seen their relations deteriorate as fighting between regime troops and rebels has intensified in Syria and the two countries have closed their airspaces to each other.
Syria has a small Armenian community of between 60,000 and 100,000 people, according to estimates, most of whom live in Aleppo.
Armenia also has close ties with Syria's major ally Russia while its relations with Turkey have long been strained.
Turkey and Armenia have no diplomatic ties and their border has been closed for more than a decade.
Turkey-Syria relations plunged further after shells fired from Syria killed five Turkish civilians inside a Turkish village on October 3.