After two weeks of vacation spent largely on the golf course in Martha's Vineyard, President Barack Obama heads home to Washington to a full diplomatic plate: Iran, China and a highly anticipated papal visit.

The 44th US president managed to remain relatively low-key during his time off, hitting the beach with his family and publishing his Spotify playlists on Twitter. The White House also made public his summer reading selection.

President Barack Obama wrote in a letter to Congress that the U.S. will uphold sanctions targeting Iran's non-nuclear activities, such as its support for Hizbullah.

Obama promised Democratic lawmakers that the U.S. will continue to keep economic pressure on Iran — and keep military options open — if his administration's nuclear deal with Tehran goes through.

The U.S. military prison in Guantanamo Bay should be shut down before President Barack Obama leaves office, Pentagon chief Ashton Carter said Thursday, saying the facility is a "rallying cry for jihadi propaganda."

He said the Department of Defense was actively searching for an alternative detention facility.

Russian President Vladimir Putin would be open to meeting with American counterpart Barack Obama on the sidelines of the U.N. General Assembly in New York, Russia's foreign minister said Wednesday. 

"Our American colleagues are sending us signs that they want to maintain contact," Sergei Lavrov said, after confirming that Putin was planning to attend the United Nations meet new month.

Robert Menendez on Tuesday became the second U.S. Senate Democrat to oppose President Barack Obama's nuclear deal with Iran, but momentum within the party nevertheless appeared to be favoring the accord.

Despite Menendez joining a congressional chorus of disapproval of the landmark but controversial pact, Senate Republican Majority Leader Mitch McConnell conceded that Obama likely had the votes to ensure the deal's survival.

The White House said Tuesday it had hired its first openly transgender official, a move which supporters said underscored the administration's drive against inequality.

Officials said former activist Raffi Freedman-Gurspan began work on Tuesday in a team that recruits personnel to serve the president.

U.S. President Barack Obama will host a summit in New York next month of leaders of the international coalition fighting Islamic State jihadists in Syria and Iraq, diplomats said.

The summit on countering violent extremism on September 29 comes one year after Obama vowed to crush IS during his United Nations speech.

U.S. Secretary of State John Kerry accused China and Russia of "very likely" reading his emails Tuesday, adding that the U.S. has and will continue to discuss cyber attacks with China.

"The answer is it is very likely. It is not ... outside the realm of possibility, and we know that they have attacked a number of American interests over the course of the last days," Kerry said on the TV show CBS Evening News.

A bipartisan group of U.S. senators Tuesday urged President Barack Obama to highlight human rights concerns when his Chinese counterpart Xi Jinping visits next month, in particular Beijing's "extraordinary assault" on rule of law.

"We urge you to make human rights and political reform in China a key and public component of the agenda for your discussions," wrote the lawmakers, including Senate Armed Services Committee chairman John McCain, ranking Senate Foreign Relations Committee Democrat Ben Cardin, and number two Senate Republican John Cornyn.

U.S. President Barack Obama has predicted that opposition to his nuclear deal with Iran will erode as the agreement is implemented and a "parade of horribles" fails to materialize.

In an interview recorded before Obama left on vacation Friday, he said Ronald Reagan faced similar Republican criticism when he decided to talk to the Soviet Union's Mikhail Gorbachev.