Is Karachi the new target for Pakistan's Taliban?

A suicide bomber killed 43 people in the southern commercial capital, Karachi, and triggered violent riots.

The Taliban, who reject any ties with Western powers and want to rule Pakistan with their radical brand of Islam, claimed they carried out the attack and warned of more violence.

Here are some questions and answers about the impact of violence in Karachi, Pakistan's biggest city.

Is this a new strategy for the Taliban?
It is hard to say. But whatever the case, the attack will raise fears the group has opened a new front against financial targets, stepping up pressure on a government already grappling with an economy in virtual recession.

Bombings, mostly in the northwest, the Taliban's stronghold, have killed hundreds of people in retaliation for a security offensive in mid-October.

Why does Karachi matter?
A wave of attacks against Karachi, a teeming city of 18 million people that is home to key financial institutions like the stock market, would distress investors.

As the industrial hub, it generates 68% of the government's revenue and 25% of Pakistan's gross domestic product. It is also home to two of the country's main ports.

While investors in Pakistan have got used to almost daily violence in the northwest, bloodshed in Karachi has a much more direct impact on financial markets and investor sentiment.

The suicide bomber attacked a Shi'ite procession despite heavy security. Angry residents torched hundreds of shops, an image carried repeatedly on local television stations, creating the impression that security forces had lost control.

Was the Karachi attack unusual?
Karachi has a long history of ethnic, religious and sectarian violence. It has been spared the brunt of militant violence. But there had been signs that the Taliban have designs on the city.

Authorities say they thwarted a number of attempts to target Karachi in recent months, including an attempted attack on an oil storage facility near the main port in September.

What does Monday's attack mean?
The bloodshed illustrated how the Taliban, whose bastions are in the tribal, lawless northwest, have extended their reach to major cities in their drive to topple the government.

The militants, analysts say, are bent on destabilising the state and Karachi provides them with a highly visible target.

Such attacks may signal new Taliban priorities.

Karachi's mayor describes the city as a revenue engine of the Taliban, saying the militant group finances its war through kidnapping and drug trafficking here. He said militants were deliberately not targeting Karachi in order to keep cash flowing.

Tighter security crackdowns have left the militants with fewer chances of carrying out attacks in the northwest, where the United States wants Pakistan to wipe out militants who cross over to Afghanistan to attack US- and Nato-led forces.

Facing pressure there, they may be planning more attacks in Karachi.

Is sectarian violence a big worry?
Attacks on the Shi'ite minority sect are not unusual. But the timing of this attack and its scale suggest the Taliban may want to trigger widespread sectarian violence to make it more difficult for security forces to stabilise the country.