A powerful explosion rocked downtown Kabul on Monday evening, according to AFP reporters, the second blast of the day to hit the Afghan capital.

A powerful explosion rocked downtown Kabul on Monday evening, according to AFP reporters, the second blast of the day to hit the Afghan capital.

Officials were trying to determine the exact location of the explosion and there were no immediate reports of casualties, Kabul police spokesman Abdul Basir Mujahid told AFP.

An interior ministry spokesman said the blast was caused by a car bomb.

Earlier Monday, a suicide bomber struck a street leading to Kabul's international airport, but no casualties were reported.

No group immediately claimed responsibility for the bombings, which comes as Afghan forces battle to end an hours-long siege near the Indian consulate in the northern city of Mazar-i-Sharif.

The spike in violence coincides with a renewed international push to revive peace talks with the resurgent Taliban.

Islamabad is set to host a first round of dialogue between Afghanistan, Pakistan, the US and China on January 11 to lay out a comprehensive roadmap for peace.