Twitter Inc unveiled technology to boost security for its users, following a spate of attacks on accounts of prominent media outlets including the Associated Press, the Financial Times and The Onion. By Jim Finkle.

HERZLIYA, Israel, May 22 (Reuters) - Israel is poised for a large-scale assault on Syria to prevent advanced weapons reaching jihadi rebels or Hezbollah guerrillas in Lebanon if President Bashar al-Assad is toppled, Israel's air force chief said on Wednesday.

Iran is pressing ahead with the construction of a research reactor that Western experts say could eventually produce plutonium for a nuclear weapon if Tehran decides to make one, a U.N. report showed on Wednesday. By Fredrik Dahl.

Metals swap deals with Iran by Switzerland-based commodities giants Glencore Xstrata and Trafigura could have been a way of skirting international sanctions against Tehran over its nuclear program, according to a confidential U.N. Panel of Experts report seen by Reuters on Wednesday. By Louis Charbonneau and Michelle Nichols.

An FBI agent shot and killed a man of Chechen origin who turned violent while being questioned on Wednesday about his connection to Tamerlan Tsarnaev, one of two Chechen brothers suspected of carrying out the Boston Marathon bombings. By Barbara Liston and Mark Hosenball.

The Federal Reserve's monetary stimulus is helping the U.S. economy recover but the central bank needs to see further signs of traction before taking its foot off the gas pedal, Fed Chairman Ben Bernanke said on Wednesday. By Pedro da Costa and Alister Bull.

A man was hacked to death in a street near an army barracks in London on Wednesday in what Prime Minister David Cameron said appeared to be a politically motivated attack. By Li-mei Hoang.

A US Senate panel on Tuesday approved legislation to give millions of illegal immigrants a path to citizenship, setting up a spirited debate next month in the full Senate over the biggest changes in immigration policy in a generation. By Rachelle Younglai and Caren Bohan.

An 78-year-old French far-right activist committed suicide at the altar of the Notre Dame cathedral on Tuesday by shooting himself in the mouth, three days after a law legalising same-sex marriage came into effect. By Lucien Libert.

At least 91 people, including 20 children, were feared killed when a 2 mile wide tornado tore through an Oklahoma City suburb, trapping victims beneath the rubble as one elementary school took a direct hit and another was destroyed. By Alice Mannette and Ian Simpson.

Jose Mourinho will quit Real Madrid at the end of the season after coming to a mutual accord with the Spanish club that brings to an end a disappointing three-year stint by his high standards. By Iain Rogers.

President Barack Obama urged the president of Myanmar on Monday to take steps to halt violence against Muslims in his country and move ahead with economic and political reforms. By Paul Eckert.

India and China will study new ways to ease tensions on their ill-defined border after an army standoff in the Himalayas, Chinese Premier Li Keqiang said on Monday on his first official foreign trip. By Frank Jack Daniel and Rajesh Kumar Singh.

Ray Manzarek, a founding member and keyboardist of 1960s rock group The Doors, died on Monday at age 74, the group's manager Tom Vitorino said.

The top Palestinian negotiator with Israel on Monday threw his weight behind U.S. Secretary of State John Kerry's bid to revive stalled peace talks, while describing the situation in the West Bank as apartheid worse than that suffered in South Africa. By Michelle Nichols.

Sci-fi movie "Star Trek Into Darkness" journeyed to the top of weekend box office charts as the latest voyage of the Starship Enterprise pulled in $70.6 million at U.S. and Canadian theaters.

Pope Francis warned the Catholic Church to not close in on itself at a Mass to mark Pentecost Sunday attended by more than 200,000 people, urging the faithful to be open and present in a new and changing world. By Catherine Hornby.

Gunmen killed a senior female politician from a reformist party in Pakistan on Saturday night, the latest violent incident in a bloody election campaign and one that set off a war of words between two major opposition parties. By Katharine Houreld.

South Africa's National Union of Mineworkers said it would seek pay rises of up to 60 percent from gold and coal producers, raising the prospect of fresh strikes as firms battle higher costs and falling prices in an already heated labour climate. By Ed Stoddard.

Germans lamented their unexpectedly poor showing at the Eurovision Song Contest, blaming Chancellor Angela Merkel's tough stance in the euro zone crisis for their failure to win any points from 34 of the 39 countries voting.

North Korean forces have seized a Chinese fishing boat, Chinese officials told state-run news agency Xinhua late on Sunday, creating a potential new irritant in ties between the two allies. By Adam Jourdan.

Nigeria offered an amnesty on Sunday to Islamist militants who surrender and said 17 people had been killed on the fifth day of a military operation to try to crush the Boko Haram insurgency in the country's northeast. By Joe Brock.

A Bangladesh factory where Wal-Mart Stores Inc and Inditex SA inspectors spotted cracks in the wall this month is still making Wrangler shirts for the world's largest apparel maker, US-based VF Corp. By Serajul Quadir and Rafiqur Rahman.

The Justice Department's seizure of phone records for journalists at the Associated Press is hurting the agency's ability to gather news, the wire service's Chief Executive and President Gary Pruitt said on Sunday.

Overtaking Apple Inc as the world's leading maker of smartphones has stretched Samsung Electronics Co's in-house supply lines, and the South Korean firm is now courting some of its rival's main parts suppliers. By Miyoung Kim.

Russian Foreign Minister Sergei Lavrov said Iran must take part in a proposed international conference to end Syria's civil war, but that Western states wanted to limit the participants and possibly predetermine the outcome of the talks. By Thomas Grove.

President Barack Obama said on Thursday he reserved the right to resort to both diplomatic and military options to pressure Syrian President Bashar al-Assad but insisted that U.S. action alone would not be enough to resolve the Syrian crisis. By Nick Tattersall and Matt Spetalnick.

Washington's top tax official was fired on Wednesday as President Barack Obama sought to stem a rising tide of criticism in a scandal over the Internal Revenue Service's targeting of conservative groups for special scrutiny. By Kim Dixon and Matt Spetalnick.

A music video shot aboard the International Space Station went viral on Monday, turning an astronaut into an overnight music sensation with his zero-gravity version of David Bowie's hit "Space Oddity." By Irene Klotz.