(CNN) -- Three people were killed and more than 30 injured in back-to-back explosions near the headquarters of an anti-Taliban political party in Karachi, Pakistan, police told CNN on Saturday.
The explosions, about 30 minutes apart, took place near the headquarters of Muttahida Quami Movement, or MQM, police spokesman Mureed Abbas said.
One device was placed in a rickshaw, police said. The second was buried in the ground.
The MQM, which is one of Pakistan's largest and most liberal parties, has been targeted by the Pakistani Taliban in recent weeks. The party is firmly opposed to the Islamist militant group.
In a call to CNN after the explosions, Pakistani Taliban spokesman Ihsan Ullah Ihsan said his group claimed responsibility.
President Asif Ali Zardari strongly condemned the bomb blasts and expressed sympathies for those killed and injured and their families.
The MQM's coordination committee condemned the two bomb blasts and called for businesses and transportation providers in the province to shut down Sunday to observe a day of mourning.
A candidate in this month's national elections was shot and killed Thursday by two gunmen on a motorbike, a senior police official in Hyderabad said. Candidate Fakhar Ul Islam was targeted on his way home from his office and was a member of MQM.
Pakistani Taliban leader Hakimullah Mehsud has told Pakistanis to stay away from the elections.
On Friday, gunmen on a motorbike in Karachi shot and killed Sadiq Zaman Khattak and his 4-year-old son when they were leaving a mosque, said Zahid Khan of Awami National Party, another anti-Taliban liberal party. Khattak, representing the Awami National Party, had been a candidate for a seat in the National Assembly.
On Saturday, Raza Haroon, a member of the MQM's coordination committee, deplored how terrorists have been targeting candidates and workers of his party, the ANP and the ruling Pakistan People Party.
Haroon charged that the election commission, the government and law agencies were playing a role of silent spectators.
But Haroon said his party wouldn't be cowed.
On May 11, Pakistanis will go to the polls to elect a new civilian government for a five-year term.
CNN's Aliza Kassim contributed to this report.