Taliban claim bombing in Karachi

Pakistan's Taliban have said they carried out the suicide bombing which killed 43 people in the commercial capital, Karachi, on Monday.

A spokesman threatened to carry out more such attacks in the coming days.

Meanwhile, firefighters are still trying to douse flames following rioting after the attack on a Shia Muslim march.

Dozens of people were injured in the bomb, which struck as Shias marked the climax of the holy month of Muharram.

After the explosion, marchers turned their anger on ambulance workers, security forces and journalists.

'Our man'

"We carried out the suicide bombing in Karachi," the AFP news agency quoted Asmatullah Shaheen, one of the commanders of Tehrik-e-Taliban Pakistan (TTP) as saying.

"He [the bomber] was our man. His name was Hasnain Muawia and we did it to protect the honour of the companions of the holy prophet," said Mr Shaheen whose name is on a government list of 20 most-wanted militants.

"We will carry out more such attacks and also target government installations," he said.

Meanwhile, fire tenders in Karachi were still struggling to control the fires that erupted following Monday's attack, officials said.

Arsonists set on fire nearly 2,000 shops and warehouses between Light House and Boulton Market in central Karachi.

The area houses Pakistan's largest wholesale markets that supply goods all over the country.

Traders said hundreds of shops were gutted in fire and that they had lost merchandise worth more than $350m. It is estimated that thousands of people have been rendered jobless.

City fire chief Ehtisham Qadri told the BBC Urdu service that the fire was still not doused and that a dozen fire engines were working the narrow lanes of markets in the old city area.

"There are no leaping flames on the skyline, but it's far from over. It's not safe yet," Mr Qadri said.

"I cannot give a time frame to bring it under control, because the area is very congested and heavily built, with narrow lanes and small shops which retard our progress."

Pakistan has seen an upsurge in violence in recent months.

Hundreds of civilians have died in bomb attacks as Pakistan's army concludes an offensive against Taliban militants in South Waziristan and surrounding areas.

US aware 'Nigerian' prepared for terror attack

The US was aware that "a Nigerian" in Yemen was being prepared for a terrorist attack - weeks before an attempted bombing on a US plane.

ABC News and the New York Times say there was intelligence to this effect, but its source is unclear.

Umar Farouk Abdulmutallab flew from Lagos to Amsterdam before changing planes for a flight to Detroit on which he allegedly tried to detonate a bomb.

The Netherlands is to introduce body scanners on US flights within weeks.

Dutch Interior Minister Guusje Ter Horst said Mr Abdulmutallab did not raise any concerns as he passed through Amsterdam's Schiphol Airport to board the flight.

She said the airport would be able to use body scanners on all flights to the US from the airport in three weeks. Nigerian authorities also said they would start using the machines next year.

Obama denounces lapses

Ms Ter Horst said that though the US had previously not wanted the scanners to be used because of privacy concerns, Washington had now agreed that "all possible measures will be used on flights to the US".

"It is not exaggerating to say the world has escaped a disaster," she said.

US President Barack Obama has acknowledged unacceptable security failures.

He said a systemic failure allowed Mr Abdulmutallab, a Nigerian, to fly to the US on 25 December despite family members warning officials in November that he had extremist views.

The source of the intelligence about "a Nigerian" in Yemen was reported as coming from the Yemeni government or from US intercept intelligence, which can refer to intercepted e-mail and phone calls.

Mr Obama said he wanted to know why a warning weeks ago from Mr Abdulmutallab's father did not lead to the accused being placed on a no-fly list.

"We need to learn from this episode and act quickly to fix flaws in the system," Mr Obama said.

Some passengers and crew tackled Mr Abdulmutallab in his seat about 20 minutes before landing in Detroit as he allegedly tried to detonate explosives in his underwear.

Initial investigations found he had used the explosive PETN and a syringe filled with liquid.

The Dutch interior minister described the bomb as professionally made but executed in an "amateurish" way.

She said Mr Abdulmutallab had passed through standard security checks, including a metal detector and a hand baggage scan, without raising suspicions.

Nigerian airports 'safe'

Mr Abdulmutallab has reportedly told investigators that he trained in Yemen with al-Qaeda.

He was living in Yemen from August to early December, the foreign ministry said, according to an earlier report from the official Saba news agency.

He had a visa to study Arabic at an institute in the capital, Sanaa.