An American man has been extradited to the Philippines to stand trial for the murder of a retired British policeman, the Filipino justice department said Tuesday.

Timothy Noah Kaufman is accused of murdering Joseph Balmer and his Filipina girlfriend, said Daniel Daganzo, head of the international operations division of the department's National Bureau of Investigation.

French President Francois Hollande on Tuesday warned that "extreme horror" films used by terrorist groups could harm young people, after fresh footage emerged of Western hostages held by North African jihadists.

"Why this video?", said Hollande of the recording from al-Qaida in the Islamic Maghreb showing a French and a Dutch tourist they have been holding hostage for several years.

U.S. Secretary of State John Kerry on Tuesday urged Iran to use "all possible effort" to prove that its nuclear program was peaceful as the final round of talks was to begin in Vienna.

"This is a very critical week obviously in Iran negotiations," Kerry told reporters in London ahead of talks with British Foreign Secretary Philip Hammond.

The departure of NATO combat forces from Afghanistan could push India and Pakistan towards a proxy war in the troubled state, Pakistan's former military ruler General Pervez Musharraf warned in an interview with Agence France Presse.

As Pakistan's ruler, Musharraf was a key U.S. ally in its "war on terror", but he now lives under tight security in his Karachi home, facing Taliban death threats and a litany of criminal cases dating back to his near decade-long rule that ended in 2008.

U.S. President Barack Obama has ordered a comprehensive review of U.S. policy on "overseas terrorist-related" hostage cases, a letter from the Pentagon has revealed.

The missive surfaced just one day after the Islamic State group posted the beheading of yet another Western hostage, U.S. aid worker Peter Kassig, in a grisly online video.

Missouri's governor declared a state of emergency Monday and activated the National Guard state militia ahead of a grand jury decision about whether a white police officer will be charged in the fatal shooting of an unarmed black 18-year-old in the St. Louis suburb of Ferguson.

Gov. Jay Nixon said the National Guard would assist police in case the grand jury's decision leads to a resurgence of the civil unrest that occurred in the days immediately after the Aug. 9 shooting of Michael Brown by Ferguson Police Officer Darren Wilson.

Thai police said Monday they were seeking two Americans after the body parts of several babies -- probably stolen from a medical museum -- were found in five parcels destined for the United States.

The two men, aged 31 and 33, crossed into neighboring Cambodia on Sunday soon after the gruesome discovery of a baby's head, at least one foot and sheets of skin, during a routine scan of packages at a DHL package depot in Bangkok.

Pope Francis said on Monday he will visit the United States in September 2015 to take part in a Catholic Church congress on the family.

Speaking at the Vatican, the pontiff said he would travel to Philadelphia for the "World Meeting of Families," a Church-sponsored gathering that takes place once every three years.

A nuclear deal with Iran would be a rare coup for a beleaguered President Barack Obama already seeking to shape his White House legacy, but analysts caution that renewing full ties will take longer.

Iran and the United States have had no direct diplomatic relations since the 1979 storming of the U.S. embassy in Tehran, when radical students held a group of American diplomats hostage for 444 days.

President Barack Obama confirmed Sunday the death of U.S. aid worker Peter Kassig, calling his beheading at the hands of the Islamic State group "pure evil."

A video released by the militants showed the beheading of Kassig, who took the name Abdul-Rahman after converting to Islam, and that of 18 men described as Syrian military personnel.