Kenya's national police service has arrested two police officers and opened an investigation after "a shooting incident" in the eastern county of Garissa, the police service said on Sunday.

The Independent Policing Oversight Authority (IPOA), a body set up to investigate cases of police brutality, has also sent its investigators to Garissa, it said late on Saturday.

The national police service said two officers had been arrested "over a shooting incident at Soko Ng'ombe market within Garissa Township" and that the inspector general had ordered an investigation.

"The inspector general has equally directed the directorate of criminal investigations to carry out forensic analysis on the firearms used by the officers," it said.

Garissa member of parliament Aden Duale said in a Twitter post police had shot dead Aden Abdi Madobe and Muhiyadin Adow Shibin on Saturday during an "arrest mission". He did not give further details.

International campaigners have raised concerns about police behaviour in the East African nation, including during lockdown restrictions.

Rights group Amnesty International said Kenyan police had killed at least 100 people in 2020, with 21 related to Covid-19 lockdown infractions, such as curfew or mask violations.