Mohammad Arif, the man raised the alarm, told Reuters news agency: "They promised me a job but instead brought me to a house where I was kept for about 15 days with the other people before I ran away."

"These people are not volunteers. They were duped. They were promised jobs by these criminals"

Malik Mohammad Iqbal, Lahore
police chief
Iqbal said: "These people are not volunteers. They were duped. They were promised jobs by these criminals."

The doctors, from two private hospitals, were arrested later on Friday and charged with violating a ban on organ trading.

"The doctors have been arrested on charges that these operations were carried out in their hospitals without the consent of the people," Iqbal said.

"The investigation will reveal how far they were involved in this heinous crime."

Hundreds of rich foreigners travel to Pakistan every year and buy kidneys from live, impoverished donors, in a business thought to be worth millions of dollars.

Pakistan currently has no legislation governing the trade in organs but a law is going through parliament aimed at stopping their sale.