Barack Obama is weak and Ronald Reagan exuded power, Republicans say. But while conservative White House hopefuls revere the 1980s president as a foreign-policy icon, oversimplifying Reaganism may mask nuances of his diplomacy.

Appreciation for the ex-president, who died in 2004, is nothing new. Buttons and posters bearing his countenance are common at conservative gatherings.

U.S. President Barack Obama will welcome the six leaders of the Gulf Cooperation Council kingdoms in mid-May for talks on Iran's nuclear program and the conflicts in Yemen, Iraq and Syria.

The White House said the May 13 meetings at the White House and May 14 gathering at Camp David "will be an opportunity for the leaders to discuss ways to enhance their partnership and deepen security cooperation."

The Islamic State group has lost control of "25 to 30" percent of the territory it holds in Iraq after coalition air strikes and an Iraqi offensive, the Pentagon said Monday.

The radical group took control of large swathes of the north and western parts of the country months ago after an offensive and the collapse of Iraqi military units.

The White House on Friday played down warnings by Iran's leaders that they may not sign a final deal of a framework accord on their nuclear program with international negotiators.

"The test of whether or not that framework can be memorialized in a deal is not going to be a comment made... by a particular Iranian leader," senior White House advisor Ben Rhodes said.

Former U.S. secretary of state Hillary Clinton looks set to officially launch her 2016 presidential bid at the weekend -- a long-anticipated second run at the White House.

The announcement -- expected to come Sunday, according to reports citing sources in her campaign team -- would make the 67-year-old the clear Democratic frontrunner in the race to succeed Barack Obama.

Foreign Minister Delcy Rodriguez said Wednesday she pressed a visiting U.S. diplomat over Caracas' wish to have Washington revoke an order calling Venezuela a national security threat.

Rodriguez, who met with Thomas Shannon, top counselor in the State Department, urged Shannon to have Obama revoke the order. 

The White House said Wednesday it would not name those behind a cyber attack on official Washington targets last October, after reports blamed Russia.

"Our investigators have concluded that it's not in our best interest to identify the entity that may be responsible for this specific activity of concern," White House spokesman Josh Earnest said.

U.S. officials insisted Tuesday that a cyber attack late last year did not compromise White House classified systems, but refused to confirm reports Russia was behind the breach.

"There was an event last year," said deputy national security advisor Ben Rhodes. "We have classified systems that are secure,"

U.S. House Speaker John Boehner and Israeli Prime Minister Benjamin Netanyahu hailed Wednesday the "strong" ties between their nations, amid tensions between Netanyahu and the Obama administration. 

But ahead of a meeting in Jerusalem, they both avoided directly addressing negotiations between world powers and Iran over Tehran's contested nuclear program.

U.S. President Barack Obama's decision to slow the withdrawal of American troops from Afghanistan will hamper peace efforts, the Taliban said Wednesday, vowing to continue fighting.

Obama on Tuesday reversed plans to withdraw around 5,000 U.S. troops from Afghanistan this year, an overture to the country's new reform-minded leader, President Ashraf Ghani.