Pakistani soldiers stand guard near the damaged office of the Muttahida Qaumi Movement (MQM) in southern Pakistani port city of Karachi on May 4, 2013. At least three people were killed and 35 others injured when twin blasts hit Muttahida Quami Movement's (MQM) election office in Karachi on Saturday night, local political leader said.  [Photo/Xinhua]

ISLAMABAD - At least three people were killed and 35 others injured when twin blasts hit Muttahida Quami Movement's (MQM) election office in Pakistan's southern port city of Karachi on Saturday night, local political leader said.

Attacks on political parties accelerated ahead country's next general elections that are scheduled to be held on May 11. Main targets of the blasts are MQM, ANP and PPP who ruled the country by forming a coalition government until the dissolution of Assemblies on March 17.

Over 70 people have been killed and about 350 injured in the recent spate of attacks on election candidates, party offices and political rallies across the country since the formal beginning of election campaign on April 11.

Haider Abbas Rizvi, senior leader of MQM, a liberal party mainly based in Karachi, said that some unknown militants planted a bomb outside their election office and later detonated it with a remote control device.

He said that the second bomb was detonated twenty minutes later when police, residents and paramilitary troops arrived at the blast site for the rescue of blast victims.

The first bomb was planted at road side while the second was fixed in a bicycle parked near the election office.

He said that some of their party activists got injured in the blasts.

The injured people including kids and three paramilitary troops were shifted to Abbasi Shaheed hospital where five of them were said to be in critical condition.

MQM chairman Altaf Hussain condemned the blast and announced to observe Sunday as a mourning day in Karachi to express solidarity with the blast victims. He said that militant elements are striving hard to delay the elections but MQM activists would not let them do it.

He said that despite repeated attacks on MQM in the city, his party is resolute to continue its election campaign.

President Asif Ali Zardari condemned that blasts and directed hospital administration to provide best medical treatment to the injured people.

Ateeq Mir, president of traders association in the city said that all business activities would remain closed in the city to condemn the blasts.

Shortly after the blasts, Pakistan Taliban, Tehrik-e-Taliban, claimed responsibility for the bombing.

Police cordoned off the area and kicked off a search operation in the area.

The incident happened in an election office located near MQM's main head office Nine-Zero in Azizabad area of Karachi, the capital city of the country's southern Sindh province.