A suicide bomber shouted “Allahu akbar” and blew himself up in a packed mosque in northwestern Pakistan, killing at least 25 people and wounding 30 during Friday prayers, a local official said.

A splinter group of the Pakistani Taliban, Tehreek-e-Taliban Pakistan Jamaat-ur-Ahrar (TTP-JA), claimed responsibility for the blast in Payee Khan, a village in Mohmand Agency that is part of the lawless Federally Administered Tribal Areas (FATA) bordering Afghanistan.

The group said it was a revenge attack, accusing tribesmen in the area of launching an assault on its forces and of capturing militants and handing them over to the government.

“The suicide bomber was in a crowded mosque, he shouted ‘Allahu akbar’ (God is greatest) and then there was a huge blast,” Naveed Akbar, deputy administrator of Mohmand Agency, told Reuters.

Akbar added that some fatalities appear to have been caused when part of the mosque caved in from the force of the blast.

“A portion of the mosque and verandah collapsed in the blast and fell on worshippers. We are still retrieving bodies and the injured from the rubble of the mosque,” he said.

Local tribal elder Haji Subhanullah Mohmand said local tribesmen had gathered a volunteer force, killed one insurgent and captured another.

“It seems to have enraged the militants and they got their revenge by carrying out a suicide attack in a mosque today,” Mohmand said.

Pakistan’s frontier regions, which are deeply conservative and hard to access due to rough terrain, have long been the sanctuary of fighters from al Qaeda, the Taliban and other militant groups.

In 2014 the army launched a major operation in other parts of FATA including North and South Waziristan against insurgents who routinely attacked government officials and civilians.

Pakistan Prime Minister Nawaz Sharif condemned the bombing and said the “attacks by terrorists cannot shatter the government’s resolve to eliminate terrorism from the country.”

Security in Pakistan has improved in recent years – the military says “terrorist incidents” dropped from 128 in 2013 to 74 last year – but Islamist extremists continue to stage major attacks.

A bombing of lawyers in the city of Quetta killed 74 people last month, an attack claimed by both the Islamic State and Jamaat-ur-Ahrar, a breakaway faction of the Pakistani Taliban.

Jamaat-ur-Ahrar also claimed the Easter Sunday bombing in a park in the eastern city of Lahore that killed 72 people, many of them children.

Most of the myriad militant groups that stage attacks inside Pakistan seek to overthrow the government to establish an Islamic theocracy and impose a stricter interpretation of the religion than is practised in much of the country.

Other armed groups based in the country target neighbouring Afghanistan and Indian-controlled Kashmir.

The news of a suicide bomber killing over 65 people, mostly women and children in a park in Lahore, is more evidence of the fault-line that runs through Pakistan. The Pakistani Taliban have claimed the attack and we saw, first hand the impacts of extremism and sectarianism when attacks against other minorities have taken place in Pakistan since 2012. Through the Musawaat project, we have worked with minorities in Pakistan who have been at risk of such real and life threatening attacks. Sadly, this attack today, has claimed the lives of many Christians and we must all mourn and their lives have not been lost in vain. Their lives will be remembered as we take on and uncouple extremism from the lives of Pakistanis through all means possible. Pakistan deserves peace and to be away from the clutches of extremists.

The suicide attack also injured 300 people and many of the Christian community had gone to celebrate Easter in the famous Gulshan-e-Iqbal Park in Lahore. In order to celebrate the message of love and hope, they were attacked by extremists who have sought to destroy the pluralism and an Islam that historically has lived with and protected minorities. Islam in the sub-continent has mainly had a history of accepting and co-existing with other faiths even at a time when colonial rule brutally wiped out many Muslim, Sikh and Hindu communities.

Let us also not forget that the founders of Pakistan included Shia, Christians and Ahmadiyya Muslims, in alliance with the Sunni majority. Quad-e-Azam, or Mohammed Ali Jinnah, the founding politician of Pakistan repeatedly stressed the Islamic nature of Pakistan based on pluralism and tolerance. What we see now through extremists, is a direct threat to the state of Pakistan, and its entire population. Yet, today, we stand with the Christian community whose lives are under threat and whose future is one of uncertainty.