The U.N.'s chief nuclear inspector arrived in Iran on Sunday on a mission to clear up "outstanding substantive issues" on Tehran's atomic program, and called for dialogue with the Islamic state.

Before departing from Vienna airport, International Atomic Energy Agency (IAEA) chief inspector Herman Nackaerts told reporters that talks were long overdue.

Taliban negotiators have begun meeting with U.S. officials in Qatar, where they are discussing preliminary trust-building measures aimed at ending the war in Afghanistan, The New York Times reported Sunday.

Citing several former Taliban officials, the newspaper said these measures included a possible prisoner transfer.

Pakistan's prime minister said on Saturday there was "a trust deficit" between Islamabad and Washington as he criticized the resumption of U.S. drone strikes on his country's tribal belt.

Speaking the day after over 100,000 people massed in Karachi to protest the strikes, Yousuf Raza Gilani said they only served to bolster militants.

A delegation from an opposition Iranian student group met Israel's centrist opposition leader and former foreign minister Tzipi Livni in Tel Aviv on Saturday.

An Agence France Presse photographer said the Confederation of Iranian Students delegation was headed by its secretary general, Amir Abbas Fakhravar, who said he was "happy to be in Israel, the only democracy in the region."

A fire in a drug rehabilitation center in a densely populated area of Lima Saturday has killed at least 26 people and injured 12 others, authorities said.

Antonio Zavala, the commandant of the fire department, said the blaze broke out on the first floor of the center when a patient's mattress caught fire.

The head of the U.N.'s nuclear watchdog said the agency will open a branch office in Fukushima to monitor efforts to contain the world's worst atomic energy accident since Chernobyl, a report said Saturday.

The government has struggled with public trust over the nuclear energy issue since the March 11 disaster and had asked the International Atomic Energy Agency (IAEA) to open an office, which will help share information on the crisis at the Fukushima Daiichi plant.

Nigerian troops killed 11 Boko Haram Islamists during a shootout Saturday in the northeastern city of Maiduguri, a stronghold of the group blamed for more than 200 deaths this year, the army said.

A spokesman for the special military squad set up to crack down on Boko Haram confirmed the incident, and said no soldiers were hurt.

Rebels shot dead five people at a polling station in India's northeast on Saturday as voting began in the first of five local elections seen as a popularity test for the national Congress government.

The separatist rebels sprayed the voting booth with bullets, killing three election officials, a paramilitary trooper and a civilian in Thangpi, a village south of Manipur state capital Imphal, police chief Priya Singh said.

The chief U.N. nuclear inspector said Saturday that a dialogue with Iran over its atomic program was long overdue, as he prepared to depart for a visit to the Islamic republic.

"We are trying to resolve all the outstanding issues with Iran," International Atomic Energy Agency chief inspector Herman Nackaerts told reporters at Vienna airport.

Six passengers of the Italian cruise ship Costa Concordia, which ran aground off the coast if Italy two weeks ago, are suing Carnival Cruise Lines, demanding compensation totaling $460 million.

Carnival is the parent company of Costa Cruise Lines, which owns Costa Concordia.