US launches Tikrit air strikes against IS

US aircraft have launched bombing raids to support Iraqi forces fighting to recapture Tikrit from the Islamic State group after Baghdad issued a request for air power.

The offensive to take back Tikrit - executed dictator Saddam Hussein's hometown - from IS jihadists has stalled over the past week.

"I can confirm that the government of Iraq has requested coalition support for operations in Tikrit," Pentagon spokesman Colonel Steven Warren said in a statement.

"Operations are ongoing."

Other countries in the US-led coalition were expected to take part in the air strikes, officials said.

Although the United States and its allies have conducted air strikes elsewhere in Iraq, the Baghdad government pointedly had not previously asked for American help for the Tikrit offensive.

Instead, Shi'ite-led Iran has played a prominent role, providing artillery and deploying advisers to Shi'ite militias also taking part in the operation.

But the assault has become bogged down, even though the Iraqi forces far outnumber the IS militants.