U.S. President Barack Obama lacks "serious will" to combat terrorism, a top Iranian official said Friday after an Iraqi appeal for American airstrikes went unanswered.

Deputy Foreign Minister Hossein Amir Abdollahian's comments followed a statement from Obama on the Iraq crisis in which he pledged to send military advisors to Baghdad but stopped short of further action at this stage.

Russian President Vladimir Putin and his U.S. counterpart Barack Obama will discuss the situation in Ukraine, Iraq and Syria "in the coming days," a top aide said on Friday.

Speaking to reporters, Putin's top foreign policy adviser, Yury Ushakov, did not provide further details about the upcoming phone call.

U.S. General David Petraeus, a former commander of U.S. forces in Iraq, said Friday he would support targeted strikes against jihadists behind an offensive in the strife-torn country, who he said were developing into a "terrorist army".

Petraeus, who won praise for leading the troop surge that preceded Washington's exit from Iraq after a costly eight-year war, told the Daily Telegraph newspaper that the militants posed a risk to countries outside the region.

U.S. President Barack Obama warned Iran on Thursday it could end up fighting sectarian fury "in a whole lot of places" unless it helped stabilize Iraq and pushed for an inclusive, multiethnic government.

Shiite Iran could play a "constructive" role in helping ease the crisis in Iraq sparked by the lightning advance of Sunni radicals from the Islamic State of Iraq and the Levant (ISIL), Obama said. 

President Barack Obama has not decided how to respond to rampant Sunni militants grabbing swathes of Iraq, but is looking at every option short of sending U.S. combat soldiers back to war.

Officials said Wednesday that Obama had not ruled out any possible courses of action, including air strikes against Islamic State of Iraq and the Levant (ISIL) fighters.

Bush-era vice president Dick Cheney savaged President Barack Obama for his alleged Iraq policy failure Wednesday, warning that a shrinking U.S. military posture could fuel terrorism.

In a blistering op-ed in that Wall Street Journal, Cheney accused Obama of pursuing "fantasy" policies that weaken the U.S. armed forces, embolden terror networks like the Islamic State of Iraq and the Levant and reduce Washington's ability to influence global events.

The United States Tuesday unveiled "historic" steps to combat illegal fishing and proposed plans to create the world's largest marine sanctuary in a bid to help save the world's besieged oceans.

"We all know how fragile our planet can be," Obama said opening the second day of a landmark conference dubbed "Our Ocean" urging everyone to "redouble our efforts."

About 275 U.S. military personnel are being deployed to Iraq to help American personnel and protect the embassy in Baghdad, President Barack Obama said Monday in a letter to Congressional leaders.

The force, which began deploying on Sunday, has been sent "for the purpose of protecting U.S. citizens and property, if necessary, and is equipped for combat," Obama wrote.

More than 6,000 Mexican children and teens who crossed unaccompanied and illegally into the United States were repatriated in the first four months of this year, Mexican officials said Saturday.

In nearly all cases, the children had already been arrested at least once, and some more than five times, in attempts to cross the U.S. border.

The United States is "committed" to supporting Iraq as it battles Sunni militants who have seized a swathe of the country's north, Secretary of State John Kerry told his Iraqi counterpart Saturday.

President Barack Obama said he was "looking at all the options" to halt the offensive that has brought the militants within 50 miles (80 kilometers) of Baghdad's city limits, but ruled out any return of U.S. combat troops. A U.S. carrier group was ordered into Gulf waters.