US Vice President Mike Pence visited US troops in Iraq during a surprise visit to the protest-hit country on Saturday.

Iran has remained within the key limits on its nuclear activities imposed by its 2015 deal with major powers despite growing pressure from newly reimposed US sanctions, a report by the UN nuclear watchdog indicated on Friday.

US Vice President Mike Pence rebuked European powers over Iran and Venezuela on Saturday in a renewed attack on Washington's traditional allies, rejecting a call by Germany's chancellor to include Russia in global cooperation efforts.

US Vice President Mike Pence visited Jerusalem's Western Wall on Tuesday while Palestinians held a general strike after denouncing his fervently pro-Israel speech the previous day as "messianic".

US Vice President Mike Pence began a visit to Israel on Sunday after being praised as a "great friend" by Prime Minister Benjamin Netanyahu and shunned by the Palestinians over US recognition of Jerusalem as Israel's capital.

Palestinian president Mahmud Abbas's Fatah faction on Saturday called for a massive demonstration next week to protest against a visit to Jerusalem by US Vice President Mike Pence after Washington said it would recognise the holy city as Israel's capital.

US Vice President Mike Pence on Sunday denied a New York Times report suggesting he is eyeing a 2020 run for president, calling it "disgraceful and offensive."

President Donald Trump acknowledged on Friday that he is personally under investigation as part of a widening probe into alleged Russian meddling in last year's US presidential race and possible collusion by his campaign.

Donald Trump's national security adviser Michael Flynn resigned amid controversy over his contacts with the Russian government on Monday.

Former New York mayor Rudy Giuliani has emerged as a "serious" contender to become the next US secretary of state, a top aide to President-elect Donald Trump said on Tuesday.

Republican Donald Trump neared the end of his vice-presidential search on Thursday, with Indiana Governor Mike Pence and former US House Speaker Newt Gingrich appearing as the front-runners.

After months of bitter campaigning, Bernie Sanders on Tuesday offered his long-awaited endorsement for Democratic presidential hopeful Hillary Clinton, saying he would work hard to help his former rival win the White House.