COLOMBO (AFP) - Three Sri Lankan cricketers were under observation in hospital Friday after they underwent surgery following the gun and grenade attack in Pakistan, a doctor said. Tharanga Paranavitana, who had a bullet removed from his chest, is expected to be discharged later Friday, Geethanjana Mendis, director general of the Sports Ministry medical unit, told AFP. The left-handed batsman should be able to resume light training within about six weeks, Mendis said. Thilan Samaraweera, who scored successive Test double centuries in Pakistan, was the worst affected. He underwent a near three-hour operation Wednesday to remove a bullet from his left thigh muscle. Samaraweera will remain hospitalised for the rest of the week and is only expected to resume physical training in two months. Mendis, who travelled to Pakistan to assess the wounded before their return said spin bowler Ajantha Mendis also remains hospitalised, after two operations on Wednesday to remove shrapnel from his head and lower back. "He is out of danger but he should be out of action for about six weeks," the doctor said. Vice captain and wicket keeper Kumar Sangakkara was discharged on Thursday after doctors removed shrapnel from his shoulder. Assistant coach Paul Farbrace is expected to remain in hospital for two to three days after having a large piece of shrapnel removed from his right arm. Mahela Jayawardene, who was playing his last Tests as Sri Lanka's captain, was treated for a minor leg injury, while players Thilan Thushara and Sampath Lakmal also underwent hospital treatment. Security remained tight outside the privately-run Nawaloka hospital where the players were being treated. Uniformed police as well as plain-clothed officers were placed outside their hospital rooms. Six policemen and two civilians were killed in Tuesday's ambush in the Pakistani city of Lahore.