Iran and six world powers begin a final round of talks in Vienna on Tuesday aiming to overcome significant remaining differences and agree a historic nuclear deal by a November 24 deadline.

"There's still a big gap. We may not be able to get there," U.S. President Barack Obama warned last Sunday.

Six people were killed when the small Cessna plane they were in crashed in northeastern Mexico, authorities said Saturday.

The plane crashed Friday near the U.S. border in Hidalgo, Tamaulipas state. Officials had initially said that only three people had died.

The U.S. House of Representatives on Friday approved construction of the controversial Keystone XL pipeline to bring oil from Canada, but the measure could still find itself blocked in the Senate.

The project, which would bring oil from tar sands in Alberta province to US refineries, passed the Republican-controlled House by 252 votes to 161, with 31 Democrats supporting the measure.

Russia on Friday warned France of "serious" consequences unless Paris delivers by the end of this month a Mistral-class assault warship whose handover has been delayed by concerns over Moscow's role in the Ukraine crisis, a report said.

"We are preparing for different scenarios. We are waiting until the end of the month, then we will lodge serious claims," the state news agency RIA Novosti quoted an anonymous high-ranking Moscow source as saying.

Pentagon chief Chuck Hagel will unveil measures Friday designed to shore up the U.S. military's troubled nuclear force after a spate of embarrassing incidents exposed management and morale problems, officials said.

Hagel will present "a comprehensive action plan to reform the nuclear enterprise based on the results of two reviews he ordered last February," a senior defense official, who spoke on condition of anonymity, told AFP.

U.S. justice officials are scooping up mobile phone data from unwitting Americans as part of a sophisticated airborne surveillance program designed to catch criminals, the Wall Street Journal reported Thursday.

Small aircraft deployed by the U.S. Marshals Service from at least five major airports have been taking to the skies with "dirtbox" equipment designed to mimic signals from cell towers, according to the Journal.

The United States on Thursday said Russia had boosted its military flights near U.S. shores and brusquely warned Moscow to abide by international law.

Washington's concerns came only days after a European think tank warned that since Russia annexed Ukraine's southern Crimea peninsula earlier this year, "the intensity and gravity of incidents involving Russian and Western militaries and security agencies has visibly increased."

An internal review of the security lapses that allowed an intruder to scale a fence and enter the White House has revealed a string of Secret Service blunders, reports said Thursday.

The New York Times cited a Department of Homeland Security review which said "performance, organizational and technical" failures had allowed Iraq war veteran Omar Gonzalez to evade security and make his way into the building in September.

The United States hit back Wednesday at allegations by the Nigerian ambassador of failing to help fight Boko Haram militants, saying there had been "a great deal" of U.S. aid to his country.

In the past six months since the Islamic militants snatched some 200 schoolgirls in northern Nigeria, Washington has shared intelligence with the Nigerian army, begun training a new battalion and held high-level talks on the threat of Boko Haram, a U.S. official said.

Domestic politics should not be allowed to influence nuclear talks between Tehran and world powers, Iranian President Hassan Rouhani said Wednesday, alluding to the U.S. Republican party's recent Senate victory.

"If one of the member countries of the P5+1 has a domestic problem or won or lost an election, it has nothing to do with us and each country must resolve its own problems," Rouhani said in televised remarks.