Lahore, Pakistan: At least three gunmen attacked a hospital in Pakistan's eastern city of Lahore on Tuesday morning, killing 12 people and holding several hostage before escaping, a senior doctor told Reuters.

"They barged into the hospital building and opened indiscriminate fire," said Javed Ikram, Chief Executive of Jinnah hospital.

He said at least 12 people were killed in the firing while some had been held hostage.

A Reuters reporter saw the bodies of four policemen.

"There are blood patches at the entrance of the hospital building," he said.

"Pillows, biscuits and other food stuff and shoes are strewn on the floor."

People and patients who were able ran from the hospital and television footage showed exhausted looking women climbing over security fences to escape.

The attackers themselves fled after the mayhem, officials said.

"They escaped from the scene," Lahore commissioner Khusro Pervez Khan told Reuters.

"We are in hot pursuit. We are chasing them. One of them was wounded."

He put casualties lower, at five killed and three wounded.

Dozens of people wounded in Friday's attacks on two mosques of a minority religious community in the city were being treated in the hospital, which is a major institution in the city. More than 80 people were killed in those attacks.

A witness told Reuters that a police commando team had stormed into the hospital.

One hospital official, who declined to be identified, said the gunmen killed one of the attackers from Friday's assault who was being treated in the Intensive Care Unit, but other reports contradicted this.