BREAKING: Massive Explosion Outside Of Kabul Airport Near Hotel, Initial Reports Say American Soldiers Caught In The Blast

An explosion has taken place outside Kabul airport amid the evacuations of thousands of people from Western nations, the Pentagon has said.

The press secretary said the number of casualties was unclear.

Sky News correspondent Sally Lockwood said the explosion occurred near the Baron hotel, where British troops and journalists have been staying.

Sky News chief correspondent Stuart Ramsey said his sources have told him the explosion was caused by a suicide bomber blowing himself up in a canalway.

He added: "We're not certain on the number of casualties, we have to assume a number of civilians, but the initial report suggests to us that American soldiers, not British soldiers but American soldiers have been injured.

"We've heard of fatalities but we haven't been able to confirm that at this stage."

The explosion came after warnings earlier in the day that a "very lethal" terror attack could occur at the airport in a matter of hours.