A bomb blew up a police car on Thursday evening in the Tajik capital Dushanbe where the presidents of Afghanistan, Pakistan and Russia were holding security talks, an interior ministry source said on Friday. Tajikistan, a volatile nation north of Afghanistan, was hosting a summit attended by Afghan President Hamid Karzai, Pakistan's Asif Ali Zardari and Russia's Dmitry Medvedev. The source said a bomb planted inside a police car went off, wounding one officer. No one was killed. "We are trying to figure out whether it was a terrorist act or a personal grudge against this particular policeman," the source said.