At least 22 people have been killed, 14 of them female university students, and many others injured after a bomb was set off near a bus in the Pakistani city of Quetta.

A second device was then detonated at the hospital where friends and relatives had gone to visit the injured and gunmen stormed the building.

On Saturday evening, Pakistani police forced their way into the hospital that had been taken over by the gunmen, freeing 35 hostages and ending the five-hour standoff.

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Reports said the initial blast happened in the car-park of the Sardar Badur Khan Women’s University just as students were heading home after lessons. The injured were taken to the Bolan Medical Hospital where local officials and police were among the visitors. At least three people were hurt in the second blast.

Quetta has been by repeatedly rocked by violence, some of it relating to a separatist insurgency, but much of it has been carried out by Taliban fighters or other militants. Often the focus of the attacks have been members of the Hazara Shia community; some Shia students were reportedly among those targeted on Saturday.

The violence in Quetta came just hours after militants destroyed a historic house elsewhere in the province of Baluchistan that was once a home of the country’s founder, Muhammad Ali Jinnah.

The Associated Press reported that the attack involved men on motorbikes planning bombs at the 19th Century property in the mountain town of Ziarat, which then started a fire. There were three bombs in total, said senior police officer Asghar Ali Yousufzai.

The attackers also shot dead a police guard outside the residency, which had been turned into a museum dedicated to Jinnah, referred to by Pakistanis as Quaid-e-Azam or Great Leader. Jinnah, whose vision for Pakistan was of tolerant society where the rights of religious minorities would be respected, died in 1948, a year after the creation of the country.

The wooden building in Ziarat was constructed in the late 19th century. Pakistan’s founder spent his last two months there. The building has served as a museum with many of Jinnah’s belongings on display.

Babar Fateh Yaqoo, a senior government official, went on television to say there had been no threats made to the monument. “This tragedy happened which is a huge national loss,” he said. “The people of Ziarat are protesting over this incident.”