Rebels from the "Free Syrian Army" take positions during fighting with the Syrian military in Ghouta, the Damascus countryside, Syria, on Oct.12, 2015. On Oct. 25, 2015, an FSA spokesman balked at an offer for military support from Russia, which has carried out airstrikes against Syrian rebels since Sept. 30, 2015. Photo by Ammar Al Bushy/ UPI | License Photo

DAMASCUS, Syria, Oct. 25 (UPI) -- The Free Syrian Army on Sunday rejected an offer from Russia for military backing against Islamic State forces in Syria, saying Moscow could not be trusted.

The response comes one day after Russian Foreign Minister Sergei Lavrov said on state-run television his country was prepared to work with Western countries in conducting airstrikes to support FSA units fighting IS militants -- provided the United States shared intelligence on rebel positions.


Issam al-Reis, an FSA spokesman, told the BBC the Russians could not be trusted since they are "assisting a regime that indiscriminately kills their own people," referring to the government of Syrian President Bashar al-Assad.

Since late September, the Russian military has conducted airstrikes on behalf of Assad, its regional ally. Moscow says it is attacking mainly IS forces, but Western nations say a majority of the strikes have targeted more moderate opposition forces, such as the FSA, which are backed by the West and Gulf states.

Saudi Arabia's foreign minister reportedly said Assad should have no part in Syria's future -- an assertion earlier echoed by U.S. President Barack Obama and other Western leaders -- and Issam told the BBC the FSA would continue attacking forces loyal to the embattled president, who is also supported by ground forces from Iran and Lebanon's Hezbollah.

"If the Syrians stood with Assad he would not ask for invaders to come to Syria," Issam said.

Russian airstrikes earlier this month enabled the Syrian military, with backing from Hezbollah forces, to conduct countrywide offensives in a bid to regain territories lost earlier in the year. Before then, government troops had been pushed into western Syria's coastal provinces from Latakia province, in northwestern Syria, down to the capital, Damascus.

The United States has for more than a year led an international air campaign against IS militants in Syria, backing Kurdish forces and moderate Arab opposition units, such as the FSA, with airstrikes, while opposing the Assad regime, albeit without the use of military force.

The U.S.-led coalition and Russia are conducting airstrikes in Syria independent of one another, but officials from both sides have engaged in a series of talks over the matter. Lavrov and U.S. Secretary of State John Kerry reportedly spoke by telephone Saturday to discuss early plans for helping to foment democratic processes in the country.

Last week, U.S. and Russian officials announced the signing of an agreement designed to avoid conflict between both countries' warplanes in Syria.