Kenya's president says his government will spare no effort to recover all of the millions of dollars lost to a corruption scandal as diplomats representing 18 Western countries including the United States urge strong action against graft.

President Uhuru Kenyatta says "there will be no mercy for the thieves."

Kenyatta spoke a day after 24 officials were charged with corruption-related offenses in a probe linked to the alleged diversion of nearly $80 million.

The president, who won a second term last year, has been criticized for not acting against corrupt officials despite numerous vows to crack down.

In a statement, the diplomats urge strong political leadership and zero tolerance of corruption.

Kenya is ranked 143th out of 180 states by Transparency International