Top officials working for Kenya's government must undergo a lie detector test as part of a corruption crackdown, President Uhuru Kenyatta has said.

Mr Kenyatta said the test, which would determine employee "integrity", was just one part of a raft of planned measures to deal with the problem.

He was speaking after it was revealed 8bn Kenyan shillings (£59m; $78m) had gone missing from a government agency.

Some 40 civil servants are facing charges over the alleged theft.

he corruption scandal, which was brought to light by suppliers who had not been paid, saw funds allegedly stolen via the National Youth Service (NYS) through fake invoices and multiple payments.

The investigation into the NYS - a key part of Mr Kenyatta's plan to address youth unemployment - is seen as a blow to the president's pledge to stamp out corruption, made when first elected in 2013.

Mr Kenyatta's speech appears to be an attempt to get ahead of the problem.

Speaking to crowds gathered to celebrate 55 years since Kenya attained internal self-rule, he said Kenya had to eliminate "corruption in our country before it fully destroys us and the future of our children".

"Let me now mention just one part of a raft of measures that we intend to implement to tackle corruption," he said.

"As an initial step, all heads of procurement and accounts in government ministries, departments [and] agencies... will undergo fresh vetting, including polygraph testing to determine their integrity and suitability.

"Those who fail the vetting will stand suspended."