Shoaib pleaded for leniency when he spoke to the media on his return

The 32-year-old hit Asif on the thigh with a bat and has been banned until an inquiry into the episode takes place.

Shoaib insisted he struck his team-mate accidentally after being provoked by a remark from all-rounder Shahid Afridi.

But board chairman Nasim Ashraf said: "Shoaib and the others should keep their mouth shut on this issue."

All-rounder Sohail Tanvir, 22, has taken Shoaib's place in the 15-man Pakistan squad in South Africa.

The controversial fast bowler has pleaded with the PCB to show leniency to him, saying: "I ask the authorities not to ban me for a lengthy period."

Until the inquiry begins he should remain quiet Ashraf on Shoaib

But Ashraf warned him to stop making public comments until the disciplinary proceedings are complete.

"It is not helping either the team or the image of Pakistan cricket. Until the inquiry begins he should remain quiet," he added.

"There is a code of conduct in place for the players and they are violating it by speaking on this issue which has already proved damaging for us.

"Comments by the players will only reduce the morale of the team and affect them in the World Cup."

PCB chief executive Shafqat Naghmi left for South Africa on Sunday to start the inquiry.

Pakistan play their first World Twenty20 match against Scotland on Wednesday in Durban and are also in the same group as traditional rivals India.