A Pakistani-American was arrested Wednesday for plotting to cause carnage on Washington's subway system by carrying out bomb attacks with people he believed were tied to al-Qaida, officials said.

Farooque Ahmed, 34, had been allegedly observing, videotaping and photographing Metro stations in the Virginia suburbs of Washington, including stations at the Pentagon and Arlington National Cemetery, since April to plan the attacks, which would have been carried out next year.

The death toll from a tsunami and a volcano rose to more than 300 Wednesday as more victims of Indonesia's double disasters were found and an official said a warning system installed after a deadly ocean wave in 2004 had broken from a lack of maintenance.

Hundreds were still missing after Monday's tsunami struck the remote Mentawi islands off western Sumatra, where officials were only beginning to chart the scope of the devastation.

Gunmen opened fire on a car wash in western Mexico on Wednesday, killing at least 13 people, an official said. It was the third massacre in Mexico in less than a week.

The gunmen drove up to the car wash in the city of Tepic and opened fire without provocation, said the official with the attorney general's office of Nayarit state, where the city is located.

Queen Elizabeth II formally welcomed the emir of Qatar to Britain on Tuesday for a trip aimed at boosting growing trade links and both countries' bids for the football World Cup.

Sheikh Hamad bin Khalifa al-Thani shook hands with the British monarch upon their meeting in Windsor, west of London, as the military sounded a gun salute.

Iran began loading fuel into the reactor core of its Russian-built nuclear power plant on Tuesday, a move which brings the facility closer to generating electricity after decades of delay.

In a report from the plant in the southern city of Bushehr, the Arabic-language Al-Alam channel of public television said engineers "started loading the core of the Bushehr power plant with the nuclear fuel today".

A bomb attack killed six Pakistani soldiers in one of the most lawless parts of the country's northwestern tribal belt on Friday, security officials said, the third deadly attack this week.

The spate of killings of paramilitary troops in the tribal belt follows a relative lull in violence as the military and government focused on relief efforts for 20 million people hit by catastrophic floods.

An outbreak of severe diarrhea has killed at least 135 people in rural central Haiti and sickened hundreds more who overwhelmed a crowded hospital Thursday seeking treatment. Health workers suspected the disease is cholera, but were awaiting tests.

Hundreds of patients lay on blankets in a parking lot outside St. Nicholas hospital in the port city of St. Marc with IVs in their arms for rehydration. As rain began to fall in the afternoon, nurses rushed to carry them inside.

The United States will be vigilant of the energy cooperation deals made between Iran and Venezuela to make sure they do not violate sanctions against Tehran, the US State Department said Thursday.

"Venezuela like all countries has clear responsibilities," State Department spokesman Philip Crowley told reporters.

Gunshots struck the Pentagon early on Tuesday but failed to penetrate the building, officials said, as police investigated the source of the gunfire.

Pentagon police officers heard about four or five gunshots around 4:55 am (0855 GMT) fired near the south parking lot of the sprawling Defense Department headquarters, officials said.

Afghan election authorities cancelled 1.3 million votes in last month's parliamentary election, nearly a quarter of the 5.6 million ballots cast, the country's top electoral officer said Wednesday.

"The total number of ballots poured into the boxes was 5,600,000, the valid vote is 4,265,347, and the invalid vote is around 1,300,000," said Fazil Ahmad Manawi, head of the Independent Election Commission (IEC).