NAIROBI (Reuters) - Kenyan police helped two colleagues who has been arrested for suspected corruption escape custody by firing warning shots to scare off anti-graft officers holding them, the anti-graft agency said.

The two officers, who work for the Directorate of Criminal Investigations, were arrested in Nairobi on Wednesday evening in a sting operation by anti-graft officers trying to trap them with a 100,000 shilling ($975) bribe, the Ethics and Anti-Corruption Commission (EACC) said.

“The two suspects ... were arrested & handcuffed but were rescued by their colleagues from Kabete Police Station who fired several rounds of ammunition as warning shots to facilitate the escape,” the EACC said on its Twitter feed late on Wednesday.

“Officers escaped with Kshs. 100,000 trap money while handcuffed.”

The absconders were being hunted, it said.

The two officers were wanted in connection with demanding a 1 million shilling ($9,750) bribe from a foreigner, the agency said.

The police in Kenya are often ranked among the country’s most corrupt institutions, but force the release of colleagues detained on suspicion of corruption was apparently unprecedented.

The anti-graft organization Transparency International-Kenya ranked the police force as the most bribery-prone institution in its 2017 East African Bribery Index.

Kenya was ranked 143 out of 180 in the Transparency International 2017 Corruption Perceptions Index.

Dozens of Kenyan government officials and business people have appeared in court since April to face charges relating to the alleged theft of hundreds of millions of shillings from public coffers in a new drive to tackle corruption.

($1 = 102.5000 Kenyan shillings)