Pakistani militants thought to have been on the verge of carrying out a suicide bombing in Islamabad’s government district blew themselves up on Friday as police pursued their car, killing one officer, authorities said.

The interior ministry said the vehicle had been heading for a high-value target in the capital, without giving details, while Prime Minister Shehbaz Sharif said timely intervention by the police had averted a “bloodbath”.

The car exploded near police headquarters on a main road leading to a government sector where parliament and the offices of senior officials are located.

The capital was already on high alert due to threats of a high-profile attack, said Interior Minister Rana Sanaullah. “Had the car reached its target, it would have caused heavy losses,” he told Geo News TV.

Islamabad police chief Sohail Zafar said police gave chase after the car failed to stop at a checkpoint.

“As they chased it, the people inside the car blew it up,” he said, adding that four police and two civilians were injured, he said.

Zafar initially said there was a man and a woman inside the car. A police spokesman later said the woman’s presence could not be verified.

The Pakistani Taliban claimed the car bombing, saying it was revenge for the killing of one of their leaders.

“We take responsibility for the suicide attack against the enemy of Islam,” said a statement from the militants known as Tehreek-e-Taliban Pakistan (TTP), an umbrella group of Sunni Islamist and sectarian groups.

The bombing came two days after a Pakistani military operation killed 25 TTP militants after a standoff at a counter-terrorism facility.

TTP militants have been waging a campaign of bombings and suicide attacks for over a decade in a bid to run the country under a harsh brand of Islamic law. They have ramped up attacks after last month calling off a ceasefire brokered by the Afghan Taliban in May.

Pakistan’s military has launched periodic offensives in regions along the Afghan border that have served as safe havens for Islamist militants.