The United States has asked Greece to bar Russian supply flights to Syria from its airspace, a Greek official said Monday, as Moscow vowed to continue arming the regime of Bashar al-Assad.
"We received the (US) request on Saturday and are examining it," a Greek foreign ministry official said on condition of anonymity.
Washington is concerned that Moscow could be increasing its military support to the regime of President Bashar al-Assad, an issue raised by US Secretary of State John Kerry to his Russian counterpart Sergei Lavrov over the weekend.
The New York Times has reported that Russia has sent a military advance team to Syria and was taking other steps that Washington fears may signal plans to vastly expand its military support for President Bashar al-Assad.
Russia has asked Greece to permit the passage of two planes between September 1 and 24, the Greek official said.
Moscow has dismissed American concerns, saying its aid to al-Assad is nothing extraordinary.
"The Russian side has never concealed the fact that it is sending military equipment to the Syrian authorities to help them fight terrorism," Russian foreign ministry spokeswoman Maria Zakharova told AFP earlier on Monday, commenting on the Kerry-Lavrov phone talks.
A Russian senator told the country's RIA Novosti state agency that if Greece closes its air space for Russian planes Moscow would find other routes.
"This is a silly move and if Greece moves to support it then it would also be unfriendly towards Russia," senator Vladimir Dzhabarov was quoted as saying.
He suggested that Russia could turn to countries like Iran and Turkey for help.
A prominent Russian blogger suggested over the weekend that Moscow was apparently building up its military presence in Syria to help prop up Assad.
The blogger Ruslan Leviyev -- known for his investigations into Russian military activity in Ukraine -- referred to widely-circulated footage from Syria apparently showing a Russian-made BTR-82A armoured personnel carrier as well as reports on social networks that Russian paratroopers have been dispatched to Syria.
Moscow has also denied sending regular troops to prop up separatist rebels in Ukraine, leaving activists and journalists to trawl through social networks for evidence of the Russian military presence abroad.
Liberal lawmaker Dmitry Gudkov on Monday said he sent a formal enquiry to Defence Minister Sergei Shoigu, asking whether Russian troops are fighting in Syria, and if so, whether any have died or been wounded.
"I'm doubtful that the Sunnis, the Shias and Alawites of the Middle East should be dearer to Russia than its own citizens," he wrote on Facebook.