The U.S. envoy to the United Nations called Friday for an independent investigation into how the world body handled claims that French soldiers raped children in Central Africa.

U.S. ambassador Samantha Power said the investigation should focus on how quickly the accusations were raised to the relevant authorities and how promptly they reacted, as well as the necessary anonymity provided to victims and witnesses.

North Korea said Saturday it had successfully test-fired a submarine-launched ballistic missile (SLBM) -- a technology that could eventually offer the nuclear-armed state a survivable second-strike capability.

North Korean leader Kim Jong-Un, who personally oversaw the test, hailed the newly developed missile as a "world-level strategic weapon", according to a report by the official KCNA news agency.

Saudi Arabia Friday announced a humanitarian ceasefire in Yemen starting May 12, even as it stepped up retaliatory air strikes on Shiite Huthi rebels in the north of the country.

"We have made a decision that the ceasefire will begin this Tuesday, May 12, at 11:00 pm and will last for five days subject to renewal if it works out," Saudi Foreign Minister Adel al-Jubeir said at a meeting of Gulf ministers in Paris.

The U.S. vote giving Congress the right to review any nuclear deal with Iran is part of a "psychological war" against Tehran's negotiators, an Iranian official said on Friday.

"Americans in this game have given Congress this role to overview the agreement so in the talks they can pressure our nuclear negotiating team," said Esmail Kosari, a member of parliament's national security and foreign affairs committee, quoted by Fars news agency.

North Korea warned Friday that it was prepared to fire on sight without warning at South Korean naval vessels it accused of violating their disputed Yellow Sea border.

The Korean People's Army (KPA) said 17 South Korean high-speed patrol boats had crossed into the North's territorial waters in the first week of May "under the pretext" of intercepting Chinese fishing boats.

The U.S. Justice Department will conduct a federal probe into Baltimore's police department following riots triggered by the death of a black man under police arrest, the Washington Post reported Thursday.

The U.S. government is struggling to counter the Islamic State group's fast-paced online propaganda, which played a role in inspiring a failed attack in Texas this week on an exhibit of caricatures of the Prophet Mohammed.

One of the two gunmen had been in frequent contact via Twitter with an American militant from the IS group who was well known to federal authorities, according to groups that monitor extremists online.

Ukrainian President Petro Poroshenko on Thursday criticized what he termed a policy of appeasement towards Russia in the context of the separatist conflict in Ukraine's east.

"Crimes are committed today in the 21st century amid the aggression against my country Ukraine, despite the cruelest lessons of the past," Poroshenko said in the Polish port city of Gdansk.

The Pentagon on Thursday dismissed conspiracy theories about planned army exercises in Texas, saying there was no plot for a U.S. military takeover of the state as some right-wing bloggers have alleged.

Faced with more than one question about the routine exercises at a press conference, Defense Secretary Ashton Carter sought to defuse a flurry of rumors circulating about the drills.

Saudi Arabia on Thursday proposed a five-day humanitarian ceasefire in Yemen after weeks of air strikes and clashes, with top U.S. diplomat John Kerry urging Iran-backed rebels to accept the offer.

The bombing by a Saudi-led coalition has failed to halt an advance by the Shiite Huthi rebels in Yemen, and concern has been mounting over increasing civilian deaths.