Shoaib Akhtar's match-fixing claims have brought a team from the ICC's Anti-Corruption Unit to Pakistan © AFP

The ICC's Anti-Corruption Security Unit (ACSU) has begun an investigation into the claims of Shoaib Akhtar, who said last week he was offered money to under-perform in matches in South Africa and India.

Sources close to the Pakistan Cricket Board confirmed to Cricinfo that the team had arrived and investigations had begun, though there confusion remains over whether they have completed their task or are still here. One source close to the investigation said that the team had already left, having interviewed several players.

Details of the visit are currently sketchy and the ICC has refused to confirm or deny the development, maintaining that it does not comment on the movement of the ACSU. A report in Dawn claimed that the investigators had spoken to Younis Khan, who was vice-captain and stand-in captain on Pakistan's last tour to India, and Umar Gul.

The investigation comes after Shoaib told Geo TV last week, "A briefcase full of money was placed before me and I was asked to under-bowl in a match at Johannesburg but I refused. Then on tour to India I was offered money but I again turned it down." Dates were not specified on either occasion but the ICC said subsequently the claims would be investigated.

The claims came after Shoaib was handed a five-year ban over a series of breaches of the players' code of conduct, including public criticism of the PCB. Under its own code of conduct the ICC can ban a player who fails to disclose any approaches for fixing to his captain or to his team manager or to a senior board official or to the ICC's officials from one to five years.