U.S. President Barack Obama called Thursday for more growth-oriented policies in Greece, saying the austerity has not been adequate to revive the country's battered economy.

Speaking after talks with Greek Prime Minister Antonis Samaras, Obama said he was confident in his visitor's commitment to much-needed reforms.

President Barack Obama insisted Wednesday that al-Qaida's leaders were on the ropes, but admitted the threats that have closed U.S. embassies across the Middle East must be taken seriously.

His remarks to around 3,000 Marines at Camp Pendleton military base in California came after around 20 U.S. missions were shut in response to intelligence reports that an attack on U.S. interests could be imminent.

U.S. President Barack Obama and Turkish Prime Minister Recep Tayyip Erdogan spoke by phone Wednesday to discuss developments in Syria and Egypt, the White House said.

During the course of the call, requested by Erdogan, the two "discussed the danger of foreign extremists in Syria and agreed on the importance of supporting a unified and inclusive" opposition, it said in a statement.

U.S. President Barack Obama will visit Sweden in early September, the Swedish prime minister's office announced on Wednesday.

"On Wednesday 4 and Thursday 5 September, U.S. President Barack Obama will visit Sweden at the invitation of Prime Minister Fredrik Reinfeldt. It will be the first time an incumbent U.S. president pays a bilateral visit to Sweden," the office said in a statement.

U.S. President Barack Obama has decided to put off a Moscow summit with Russia's Vladimir Putin, the White House said Wednesday, citing a lack of progress in relations and 'disappointment' over the Edward Snowden affair.

Obama talked about the souring relationship with Moscow in a talk show interview late Tuesday, accusing the Russians of slipping back "into a Cold War mentality."

U.S. President Barack Obama said Tuesday he was "disappointed" by Russia's decision to grant asylum to Edward Snowden, the former intelligence contractor who leaked details of vast U.S. surveillance programs.

"I was disappointed, because even though we don't have an extradition treaty with them, traditionally we have tried to respect if there's a lawbreaker or alleged lawbreaker in their country," Obama said during an appearance on a late-night comedy show.

Russia's deputy foreign minister on Tuesday slammed the United States for questioning whether President Barack Obama would meet his Russian counterpart in September after Moscow gave asylum to fugitive Edward Snowden.

"The U.S. administration is bringing into question bilateral contact at the highest level. I think this is absolute distortion of reality, it's looking at the world in a crooked mirror," deputy foreign minister Sergei Ryabkov said in an interview with the Interfax news agency.

The White House said Monday it would decide "in coming days" whether President Barack Obama will go ahead with a summit in Moscow in early September.

The United States has said it is reviewing whether Obama will meet President Vladimir Putin in Moscow after Russia last week gave asylum to Edward Snowden, who is wanted by Washington for leaking details of U.S. surveillance programs.

Michelle Obama took to Twitter on Sunday to send her husband an affectionate birthday message -- and a gentle ribbing about the U.S. President's graying hair.

"Happy birthday, Barack! Your hair's a little grayer, but I love you more than ever," Michelle Obama wrote on her official twitter account, @FLOTUS.

The White House held a high-level meeting Saturday on terror concerns that prompted Washington to issue a worldwide travel alert and order its embassies across the Islamic world closed temporarily.

The meeting was held as Interpol issued a global security alert after hundreds of militants were set free in jailbreaks linked to the al-Qaida terror network, and as suicide bombers killed nine near the Indian consulate in the eastern Afghan city of Jalalabad.