KABUL - An explosive device went off during rush hour Tuesday morning in the Afghan capital Kabul, injuring four people, police said.

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"An explosive device was planted near the river in Muradkhani and detonated at round 8 a.m. local time (GMT 0430), leaving four passers-by injured," a police official who declined to be named told Xinhua.

Meanwhile, spokesman of the Afghan Defense Ministry General Zahir Azimi told Xinhua he did not know if there were any casualties in the explosion, adding that an investagtion was underway.

No group has claimed responsibility for the attack.