By Faris Ali

PESHAWAR, Pakistan (Reuters) - A suicide bomber blew himself up in a busy market on the outskirts of Pakistan's northwestern city of Peshawar on Sunday, killing at least five people and wounding many, police said.

The attacker targeted mayor of Matni village who was a vocal opponent of the militants. Matni is close to the lawless tribal lands where Islamist militants are active.

"So far, we have reports that five people were killed and 30 wounded," Mohammad Imran, a senior police official said.

Another police official said the mayor, Abdul Malik, was seriously wounded.

Islamist militants have unleashed a campaign of bomb and suicide attacks in Pakistan in recent weeks in retaliation for a major offensive launched by security forces in their main bastion, South Waziristan, on the Afghan border.

Last month, more than 100 people were killed in a car bombing in Peshawar in the deadliest attack in the country in two years.

More than 150 people were killed in attacks before the offensive was launched in South Waziristan.

The army went on the offensive in the ethnic Pashtun region

on October 17 aiming to root out Pakistani Taliban militants behind a wave of violence in urban areas.

Soldiers have been advancing into the militant heartland from three directions and had entered their headquarters of Makeen on Friday.

The offensive is closely watched by the United States and other powers embroiled in neighboring Afghanistan, as South Waziristan's rugged landscape of barren mountains and hidden ravines has become a global center of Islamist militancy.

(Reporting by Zeeshan Haider; Editing by Jeremy Laurence)