Men walk past the Federation Council, head Russia's upper house of parliament, in Moscow, Russia, September 30, 2015. The Federation Council voted unanimously to give President Vladimir Putin approval to deploy the country's military in Syria. [Photo/Agencies]

DAMASCUS -- The Russian air force aid to Syria has come upon the request of President Bashar al-Assad, state news agency SANA reported Wednesday.

"Sending Russian air force to Syria came upon the request of the Syrian state, which came through a letter sent by President Bashar al-Assad to President Vladimir Putin, which include an invitation to send a Russian air force as part of Putin's initiative to counter terrorism," SANA said, citing a statement from the presidential media office in Damascus.

A couple of weeks ago, Syrian Foreign Minister Walid al-Moallem said in an interview that his government could ask for a Russian military aid if necessary. A day later, Russian officials said Moscow is ready to provide aid to Syria.

Earlier on Wednesday, Russia's Federation Council, the upper house of parliament, granted President Vladimir Putin approval to send armed forces to Syria, Russian Presidential Administration Chief Sergei Ivanov said.

"The Federation Council unanimously supported the president's request," Tass news agency quoted Ivanov as saying.

According to Ivanov, only air forces would be sent to Syria to fight against Islamic State militants at the request of Syrian President Bashar al-Assad.

Earlier in the day, Putin formally requested permission from the upper house to send "contingent of Russian Armed Forces" outside Russian territories "in line with universally recognized principles and international laws," according to an online statement released by the Kremlin.

"The operation's goal is only to provide air support to Syrian armed forces in the fight against IS," Ivanov stressed.

He added that the operation would be limited in time while refusing to specify types of weapons that would be used.

Moreover, all Russia's partners and allies would be informed about the decision as well as operation details if necessary, according to Ivanov.

Under Russian Constitution, the Federation Council is responsible for deciding on the possibility of using Russian armed forces outside the country.