LAHORE, Pakistan (Reuters) - Pakistani counter-terrorism police raided a militant hideout and killed six suspected members of a Taliban faction that has launched a new campaign of violence against the government, police said on Thursday.

Since Monday, several bomb attacks across the country have shattered a period of improving security, underscoring how militant groups still pose a threat in the nuclear-armed country of 180 million people.

The Counter Terrorism Department in Punjab province said its officers surrounded a hideout of the Pakistani Taliban’s Jamaat-ur-Ahrar faction in the city of Multan late on Wednesday and ordered the suspects inside to surrender.

“But the terrorists started firing at the raiding party and threw explosives,” a spokesman for the department, who the unit does not identify for security reasons, said in a statement.

Six militants were killed while three or four escaped under cover of darkness, the department added. Two hand grenades, two automatic rifles and two pistols were recovered.

The militant faction claimed responsibility for a suicide bomb attack near the Punjab provincial assembly in the city of Lahore on Monday that killed 13 people and wounded more than 80.

Jamaat-ur-Ahrar said the attack was the beginning of a new campaign of violence against the government, security forces, the judiciary and secular political parties.

Since then, militants have killed two bomb-disposal officers in the western city of Quetta and a suicide bomber blew himself up outside a government office near the northwestern city of Peshawar on Wednesday, killing five people.

Also on Wednesday, a suicide bomber on a motor bike attacked a group of judges in a van in Peshawar, killing their driver.

On Thursday afternoon, a roadside bomb hit an army convoy, killing three soldiers in the southwestern province of Baluchistan, the military said in a statement. No group claimed responsibility for that attack.

The attacks have underlined the threat militants pose to the government of Prime Minister Nawaz Sharif despite an army offensive launched in 2014 to push them out of their strongholds near the Afghan border.

Pakistan’s foreign office said it had summoned Syed Abdul Nasir Yousafi, deputy head of mission at Afghanistan’s embassy in Islamabad, on Wednesday to voice concern about Jamaat-ur-Ahrar “sanctuaries” in Afghanistan.

Pakistan says militants launch attacks from the Afghan side of the border.

“Afghanistan was urged to take urgent measures to eliminate the terrorists and their sanctuaries, financiers and handlers,” the foreign office said in a statement.

Afghanistan and the United States accuse Pakistan of harbouring Afghan Taliban leaders fighting to topple the Western-backed government in Kabul.

Pakistan has long denied sheltering the Afghan Taliban.