NAIROBI (Reuters) - Kenya’s president ordered all state procurement personnel on Friday to undergo lie-detector tests as part of measures to tackle graft after dozens of officials and business people were detained for alleged theft of public funds.

On Monday, 54 people - including the public service ministry’s principal secretary - were named to face charges related to the stealing of nearly $100 million at the National Youth Service (NYS), a state agency that trains young people to work on projects ranging from construction to traffic control.

Dozens of the suspects remain at large, while 24 were arrested and pleaded not guilty in court on Tuesday.

“All heads of procurement and accounts in government ministries, departments, agencies and parastatals will undergo fresh vetting including polygraph testing, to determine their integrity and suitability,” President Uhuru Kenyatta said in paraphrased quotes released by his office.

“Those who shall fail the vetting (through lie-detector tests) will stand suspended. I expect this exercise to be concluded before the start of the new financial year (2018/2019),” a statement quoted him as saying at a ceremony marking Kenya’s independence from Britain in 1963.

The next financial year begins on July 1.

While Kenyatta pledged to stamp out graft when first elected in 2013, critics say he has been slow to pursue top officials. No high-profile convictions have occurred since he took office.

On Thursday, the director of criminal investigations said 10 financial institutions had come under investigation on suspicion of handling the missing funds, including the East African country’s biggest bank by assets, KCB Group, and Standard Chartered’s Kenyan business.

The case triggered protests in the capital Nairobi, where 200 people marched through the streets to protest against what they said were “high levels of corruption”.

The prosecutor’s office says it had applied for arrest warrants for suspects who failed to turn up in court on Tuesday.