Compass said that Peter Harris, chief executive of the group's UK and Ireland, Middle East and Africa division, was being dismissed along with Andrew Seiwert - chief executive of Compass subsidiary Eurest Support Services (ESS). Harris had been ESS chief executive until July.
A mid-ranking executive associated with United Nations contracting was also being dismissed.
The share price of Compass was showing a gain of 0.25 percent to 197.5 pence in late morning London trading following the news, while the FTSE 100 index of leading shares gained 0.71 percent to 5,396.40 points.
The dismissals come after Compass announced on October 21 that it had instructed law firm Freshfields Bruckhaus Deringer to conduct a probe into "the relationships between" ESS, the United Nations and IHC - a former contractor and vendor to the UN procurement department.
"The investigation has raised serious concerns as to whether, within ESS, there has been, in connection with IHC and the UN, improper conduct and a failure to comply with the company's statement of business principles," a Compass statement to the London Stock Exchange said on Thursday.
"As a result, Peter Harris, whose suspension was announced on 21 October, is being dismissed, together with Andrew Seiwert and a further mid-ranking executive who was associated with UN contracting."
Compass added that the management of ESS would be restructured. According to media allegations, international investigators have been probing alleged links between ESS and Alexander Yakovlev, a former UN procurement officer who was arrested in August on suspicion of corruption. "Compass will be continuing to cooperate voluntarily and fully as appropriate with the UN and US authorities, including the Office of the United States Attorney for the Southern District of New York," Compass said.
In recent years, ESS has won contracts with the UN to supply food to troops in trouble spots including East Timor, Kosovo and Lebanon. Compass supplied 30,000 UN peacekeepers, according its 2004 annual report and last year won contracts in Liberia, Eritrea and Burundi.
Compass, which has posted three profit warnings in a year, has noted that revenue from the UN contracts in 2004 was less than one percent of group revenues.