The Los Angeles Times reported the plane was held for several hours on Wednesday as Turkish authorities searched it. They seized 10 boxes before allowing the plane to continue to Damascus.
Tensions between Turkey and Syria have escalated in the past week as the two sides have lobbed shells at one another across the border after five civilians were killed in Turkey by shelling.
By ordering down the Syrian plane from Moscow, Turkey brought Russia into the dispute, as Moscow has supported the regime of Syrian President Bashar Assad.
U.S. officials have also criticized Russia for arming Assad’s forces in the civil war with the Syrian rebels.
White House spokesman Josh Earnest said Thursday that the White House had no comment on Turkey's decision to order the plane down.
"We stand with the Turks as they confront this range of challenges, and certainly stand with them as they work to end the flow of arms to the Assad regime," Earnest told reporters on Air Force One. "But in terms of this specific situation, I’m not able to comment on it beyond saying that we’ve seen the reports."
Turkey said it would continue to stop Syrian aircraft from using its airspace if necessary, and it also instructed Turkish planes to avoid Syrian airspace because it was no longer safe, according to Reuters.
"We are determined to control weapons transfers to a regime that carries out such brutal massacres against civilians. It is unacceptable that such a transfer is made using our airspace," Turkish Foreign Minister Ahmet Davutoglu said.