KARACHI: The Tehrik-i-Taliban Pakistan (TTP) claimed responsibility Saturday for twin bomb attacks in Karachi overnight that killed at least seven people and wounded at least 28 others.

Shahidullah Shahid, a spokesman for umbrella group TTP, told AFP that the attacks in Karachi were carried out in revenge for violence in Rawalpindi on November 15.

He said the attacks were aimed at Shias in Karachi, and vowed further violence.

“It was to avenge the Rawalpindi incident, we will carry out more such attacks to avenge the killing of Sunnis,” Shahid told AFP by telephone from an undisclosed location.

Fighting erupted in the garrison-city of Rawalpindi, which neighbours the capital Islamabad, earlier this month when a procession by Shia Muslims to mark the most important day of the mourning month of Muharram coincided with a sermon at a nearby Sunni mosque.

The groups clashed with each other, TV cameramen and security forces.

Officials said 11 people were killed and more than 60 injured while a Sunni mosque and seminary and an adjacent cloth market were burnt, with Sunni groups blaming Shia protesters.

Thousands of people in major cities across the country, including Karachi, protested amid high security on Friday after Sunni groups called for demonstrations against the Rawalpindi violence.

The explosions overnight in Karachi Friday took place within minutes of each other in the city's bustling, predominantly Shia neighbourhood of Ancholi.

Karachi, a city of 18 million people which contributes 42 per cent of Pakistan's GDP, is rife with murder and kidnappings and has been plagued with sectarian, ethnic, and political violence for years.

The TTP has been behind hundreds of bomb and gun attacks that have fanned instability in Pakistan, killing more than 6,500 soldiers, police and civilians since 2007.