KARACHI, Pakistan — A string of small explosions wounded at least 25 people Monday in the southern port city of Karachi, rattling Pakistan the day after a deadly suicide attack in the capital.
    Police said the six blasts came within about an hour of each other, striking residential and commercial spots in Karachi, a teeming city where political and militant-related violence is common.
    Officials said one of the blasts hit a taxi stand and another was in a pickup truck full of scrap metal.
    There was no immediate claim of responsibility for the blasts. Babar Khattak, Sindh province police chief, said that it appeared five to seven ounces of explosives were used in each.
    ‘‘It seems the series of blasts was carried out to create harassment and fear among the citizens,’’ Khattak said. He also noted areas struck had large populations of Pashtuns , and said the explosions may have been aimed at creating ethnic unrest.
    Interior Ministry chief Rehman Malik said the blasts appeared to have been aimed at destabilizing the city, Pakistan’s commercial hub, which has a mix of religious and ethnic groups and a history of sectarian and ethnic strife.
    It was not clear how many of the 25 wounded were civilians or how badly they were hurt.
    Television footage showed ambulances rushing people through Karachi’s crowded streets to hospitals and victims lying in hospital beds with bloody bandages.
    In October, former Prime Minister Benazir Bhutto narrowly escaped a suicide attack in Karachi that struck a rally of thousands of supporters welcoming her home from exile.
    More than 140 people were killed in that attack. Bhutto was later slain in a separate attack in December in Rawalpindi.
    Khattak said security forces had intensified patrols in the affected Karachi areas Monday.
    There has been no claim of responsibility for the Sunday blast in Islamabad, which left at least 18 people dead, most of them police officers
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    Associated Press Writer Sadaqat Jan contributed to this report.