US president Barack Obama enjoys a golf session in Oak Bluffs, Massachusetts, on the island of Martha's Vineyard (AP)

Barack Obama has interrupted his holiday to return to Washington for meetings with vice president Joe Biden and other advisers on the US military campaign in Iraq and the protests in Ferguson, Missouri.

The White House has been cagey about why the president, who has received multiple briefings on both issues while holidaying at Martha's Vineyard, Massachusetts, needs to be back in the capitol for the discussions.

The White House announced Mr Obama's plans to return to Washington before the US air strikes in Iraq began and before the shooting of an unarmed black teenager in Ferguson that sparked violent protests.

Part of his decision appears to be aimed at countering criticism that Mr Obama is spending two weeks on a resort island in the midst of so many foreign and domestic crises.

Those issues turned the first week of the president's holiday into a working break. He made on-camera statements on Iraq and the clashes in St Louis suburb Ferguson. He also called foreign leaders to discuss the tensions between Ukraine and Russia, as well as between Israel and Hamas.

"I think it's fair to say there are, of course, ongoing complicated situations in the world, and that's why you've seen the president stay engaged," White House spokesman Eric Schultz said.

Mr Obama is due to return to Martha's Vineyard tomorrow and stay through next weekend.

Even though work has occupied much of his first week on holiday, Mr Obama still found plenty of time to golf, go to the beach with his family and dine on the island.

He hit the golf course one more time yesterday, before of his departure, joining two aides and former basketball star Alonzo Mourning for an afternoon round. He then joined wife Michelle for an evening jazz performance featuring singer Rachelle Ferrell.

There have also been a dose of politics. Mr Obama headlined a fund raiser on the island for Democratic Senate candidates and attended a birthday party for Democratic adviser Vernon Jordan's wife, where he spent time with former president Bill Clinton and his wife Hillary.

That get-together between the former rivals-turned-partners added another complicated dynamic to Mr Obama's break. Just as he was arriving on Martha's Vineyard, an interview with former secretary of state Mrs Clinton was published in which she levied some of her sharpest criticism of Mr Obama's foreign policy.

Mrs Clinton later promised she and Mr Obama would "hug it out" when they saw each other at Mr Jordan's party. No reporters were allowed in, but the White House said the president danced to nearly every song.

Meanwhile the US has expanded its air campaign in Iraq with attacks aimed at helping the country's forces regain control of the strategic Mosul dam.

Mr Obama told Congress yesterday that the widened mission would be limited in duration and scope.

The administration's letter to members said "the mission is consistent with the president's directive that the US military protect US personnel and facilities in Iraq, since the failure of the Mosul dam could threaten the lives of large numbers of civilians and threaten US personnel and facilities - including the US embassy in Baghdad".

It also noted that the failure of the dam could "prevent the Iraqi government from providing critical services" to its people.

White House spokeswoman Caitlin Hayden said the operations were being undertaken in conjunction with and at the request of the Iraqi government.

The latest round of US air strikes in Iraq against the Islamic State extremist group includes the first reported use of land-based bombers in the military campaign.

Kurdish security officials said Kurdish forces, aided by US and Iraqi air strikes, had taken over parts of the dam, which was captured by the Islamic State militants less than two weeks ago.

The US military said its forces conducted nine strikes on Saturday and another 16 yesterday. The second round of attacks damaged or destroyed 10 armed vehicles, seven Humvees, two armoured personnel carriers and one checkpoint.

PA Media