The United States is ready to help fund the demobilization of Democratic Republic of Congo's rebels, a senior U.S. official said on Saturday as Secretary of State John Kerry arrived in the country on the latest leg of an Africa tour.

"I can say categorically that we’re ready to support them," the official said when asked if Washington was ready to back the government's demobilization plan for some 12,000 rebels active in dozens of militias in the country's mineral-rich, restive east, a plan that's estimated to cost some 100 million dollars. 

U.S. President Barack Obama will visit Poland in June as part of a European tour that will also include stops in France and Belgium, Vice President Joe Biden announced Wednesday.

The visit to Poland comes as Washington tries to allay the concerns of its allies over the escalating crisis in neighboring Ukraine. 

Western countries urged Lebanese officials on Friday to elect a new president within the constitutional deadline, voicing fear of vacuum at the helm of the country's highest Christian post, which will have negative impacts on Lebanon.

Informed sources reiterated in comments published in As Safir newspaper the U.S. administration's stance, which highlights the importance of “carrying out the polls on time and avoid vacuum.”

France and the United States called Wednesday for the U.N. Security Council to consider sanctions against South Sudan over spiraling violence in the country's civil war, diplomats said.

U.S. ambassador Samantha Power relayed Washington's position in a closed-door meeting of the 15-member Council, diplomats said, and France's Gerard Araud told reporters before the session that it was time to think about sanctions against those responsible.

Iran brought its simmering row with the United States over its proposed U.N. ambassador to United Nations headquarters on Tuesday but failed to make any headway.

U.S. President Barack Obama signed into law Friday a bill designed to bar Iran's pick for U.N. ambassador from U.S. soil over his links to the 1979 American embassy hostage siege.

The United States said Tuesday it was watching "very closely" following South Korean warnings that North Korea may be preparing a fourth nuclear test ahead of a visit to Seoul by President Barack Obama.

"North Korea has a history of taking provocative action and we are always mindful of the possibility that such an action could be taken," White House spokesman Jay Carney told reporters aboard Air Force One as Obama departed for his week-long trip to Asia.

Five years after refashioning U.S. foreign policy to emphasize Asia, President Barack Obama will face questions over his strategy's content and staying power in the region this week.

Obama will counter the impression that events, including carnage in Syria and the East-West showdown over Ukraine have dragged his administration’s attention elsewhere.

The U.S. ambassador to the U.N. urged Myanmar on Thursday to intervene to stop communal violence there and protect humanitarian workers in the volatile western state of Rakhine.

Myanmar, formerly called Burma, has been shaken by religious unrest in recent years with at least 250 people killed in Buddhist-Muslim clashes since 2012.

The United States warned Wednesday it was "actively preparing" new sanctions to hit Russia if critical Ukraine talks do not produce concessions from Moscow.

U.S. officials privately signaled they had little hope that the Geneva talks between Russia, Ukraine, the European Union and Washington would make significant progress.

The United States is coordinating with its European allies on "additional steps" to slap more sanctions on Russia over the crisis in Ukraine, a U.S. official said Tuesday.

Secretary of State John Kerry spoke by phone with his French, German and British counterparts Tuesday, but new sanctions are unlikely to be unveiled before crunch talks slated for Thursday in Geneva, State Department spokeswoman Jen Psaki told reporters.