The U.S. military says it halted an air raid against the Islamic State group in eastern Syria after being told by Russia that it might have struck Syrian government forces, resulting in the deaths of 62 Syrian soldiers, according to Maj. Gen. Igor Konashenkov, a Russian Defence Ministry spokesman.

The U.S. Central Command statement was issued late Saturday, after Syria and Russia said the U.S.-led coalition had struck a Syrian military base in Deir el-Zour that is surrounded by IS militants, enabling them to advance.

The statement says "the airstrike was halted immediately when coalition officials were informed by Russian officials that it was possible the personnel and vehicles targeted were part of the Syrian military."

It says "coalition forces would not intentionally strike a known Syrian military unit."

A U.S. military official said he was "pretty sure" targets mistakenly hit in the coalition strikes were Syrian forces.

Russian Defence Ministry spokesman Igor Konashenkov says a U.S. airstrike on Saturday took place near the Deir el-Zour airport in eastern Syria. (Google/CBC)

'Serious and blatant attack on Syria'

Konashenkov says the airstrike on Saturday took place near the Deir el-Zour airport in eastern Syria and was carried out by two F-16s and two A-10s.

He did not identify the planes' country affiliation, but said they were part of the international coalition.Konashenkov says Syrian authorities told the Russians that 62 soldiers were killed and more than 100 wounded.

He says the planes came from the direction of the border with Iraq.

In this June photo released by a militant website, ISIS fighters fire weapons toward Syrian troops in Deir el-Zour. The Syrian military said a U.S. airstrike that reportedly hit Syria forces enabled an ISIS advance on a hill overlooking an air base in the region. (Associated Press)

The Syrian military said the airstrike enabled an ISIS advance on a hill overlooking the air base. It called the strike a "serious and blatant attack on Syria and its military," and "firm proof of the U.S. support of Daesh and other terrorist groups," using the Arabic acronym for IS. President Bashar Assad's government views all those fighting against it as "terrorists," and has long accused the U.S. and other rebel supporters of backing extremists.

The U.S. is not known to have directly struck Assad's forces at any point during the five-year civil war.

Emergency UN meeting scheduled

The UN Security Council meets today at the request of Russia, diplomats said. The 15-member body is due to meet behind closed doors at 7:30 p.m. ET.

A Russian Defence Ministry spokeswoman, Maria Zakharova, says Russia wanted an emergency meeting of the UN Security Council to discuss the strike.

Zakharova said the strike jeopardized a Russian-U.S. agreement on Syria and looked like evidence that Washington was helping Islamic State militants.

Russian Foreign Ministry spokeswoman Maria Zakharova says Russia wants an emergency UN Security Council meeting to 'demand a full and detailed explanation from Washington.' (Maxim Shemetov/Reuters)

"We are reaching a really terrifying conclusion for the whole world: That the White House is defending Islamic State. Now there can be no doubts about that," the RIA Novosti news agency cited Zakharova as telling the Rossiya-24 TV station.

"We demand a full and detailed explanation from Washington. That explanation must be given at the UN Security Council."

A senior Obama administration official says the U.S. has "relayed our regret" for the unintentional loss of life.

The official says the notification was sent through Russia. The official also says the U.S. will continue to pursue compliance with a cessation of hostilities as it continues military action against ISIS and an al-Qaeda-affiliated group in Syria. The official was not authorized to discuss the notification by name and requested anonymity.

Syria's foreign ministry called for the UN Security Council to condemn what it called U.S. aggression and require Washington to respect Syrian sovereignty, it said in a statement carried on the country's state-owned media.