Pakistan pace bowlers Shoaib Akhtar and Mohammad Asif have been ruled out of the World Cup due to injury, a senior cricket board official said on Thursday.

The double withdrawal comes just five months after the pair tested positive for the anabolic steroid nandrolone and banned by their national board before an appeal panel cleared them to play again.

Shoaib, who has played only one Test and four one-dayers since February 2006 due to fitness concerns, has not recovered from the knee injury that forced him to be sent back from South Africa last month.

Asif has been carrying a niggling elbow problem since that tour and the pair were receiving treatment in London, but neither will be fit enough to take part in the tournament in the Caribbean, which starts on March 13.

"The doctors have said they require at least another three weeks to make a complete recovery from their injuries. We couldn't wait for that long," Pakistan Cricket Board chief selector Wasim Bari told reporters.

"Yasir Arafat and Mohammad Sami will be sent as their replacements."

The loss of the new-ball pair comes as a major setback to Pakistan's hopes before their opening match against the West Indies on the first day of the tournament.

Captain Inzamam-ul-Haq said his team has not had a perfect build-up with Shoaib and Asif joining all-rounder Abdul Razzaq as high-profile withdrawals from the squad.

"Certainly it is not an ideal situation for us. Losing three experienced players is a big disappointment," Inzamam said.

"But we just have to manage with the players we have and they are capable of doing well."

"It is a big blow for us, but I am confident that Yasir Arafat and Mohammad Sami will live up to the expectations," team coach Bob Woolmer said.

"They will join the team in a week's time and we hope to overcome our injury problems with a united team effort."

TESTED POSITIVE

Shoaib and Asif have faced a number of problems since testing positive for the banned substance nandrolone last October in out-of-competition tests carried out by the PCB before the Champions Trophy in India.

Initially, the 31-year-old Shoaib was banned for two years and Asif for one year by a drugs inquiry tribunal, but an appellate panel of the board later exonerated them of doping charges and lifted the suspensions.

The incident led to the Pakistan board holding in-house dope tests for the players and reserves in the World Cup squad.

All the players appeared and passed the tests except Shoaib and Asif, who were being treated for their injuries in Britain.

Sources within the board said the decision to drop the players on the eve of the team's departure for the West Indies might have come as a result of an unusually strong statement about doping issued by the International Cricket Council on Thursday.

ICC chief executive Malcolm Speed said that Shoaib and Asif could face doping tests as soon as they arrived in the Caribbean for the World Cup.

He also described their continuing to play international cricket as an embarrassment for the sport.

"The ICC had made it's position very clear and the board could no longer take a risk of them facing drug problems again in the World Cup," one source said.

Medical experts say that traces of nandrolone remain the body for up to six months.

Pakistan media have reported extensively that Shoaib and Asif went to London to have private drugs tests to confirm if the substance remained in their bodies before the World Cup.