PESHAWAR, Pakistan - Three people were killed yesterday in a suicide bombing outside a club for Pakistani journalists in this northwestern city, as Islamist extremists continued a two-month spree of violence that has further destabilized this politically fragile nation.

At least 20 people were wounded in the attack by a young man who approached the gate of the Peshawar Press Club and detonated his explosives when a police guard attempted to search him. The bomber killed the guard, a club accountant and a female bystander, said Shamim Shahid, the press club's president.

The bombing came as political turmoil roils Pakistan, distracting the weak civilian government from its battle against a rising insurgency that unleashed a campaign of violence across the nation in October.

President Asif Ali Zardari has faced calls to resign since a Supreme Court decision last week threw out an amnesty that had shielded him and many other top government officials from graft charges.

Militants have called the string of attacks a response to a military operation against the Pakistani Taliban in a mountainous region near the Afghan border.

No area of the country has been hit harder than Peshawar, the volatile capital of the province edging that region. Though most attacks have targeted security forces, militants have also struck a market, a mosque and now - for the first time, authorities said - reporters in the city.

Extremists have threatened, attacked and killed journalists in attempts to prevent reporting they deem critical of the Taliban, and journalists also say they face pressure from government operatives trying to influence news coverage.

The combination has made Pakistan one of the most dangerous environments for journalists, rivaling conflict zones like Iraq and Somalia, according to media watchdogs.

At least 45 journalists have been killed in Pakistan since 2001, the year Pakistan joined the U.S. in its fight against the Taliban and al-Qaeda, said Mazhar Abbas, until recently secretary general of the Pakistan Federal Union of Journalists.

The press club, a popular gathering spot for journalists in the restive city, had received recent threats and boosted its security in response, Shahid said.

He said those measures probably kept the bomber from reaching the organization's building and exacting a greater toll.