Kenya's police have said the fatal shooting of a lawmaker by a gunman aboard a motorcycle in the capital Nairobi appeared to be targeted and premeditated.

Charles Were, a member of parliament representing Kasipul constituency in Kenya's west, was shot dead at around 7:30 p.m. (1630 GMT) when his vehicle was stopped at a traffic light on Ngong Road, police said in a statement released late on Wednesday.

According to witnesses, the shooter was riding as a passenger on a motorcycle that stopped alongside the car, police said.

"The pillion passenger approached the vehicle and fired shots at the passenger side before jumping back onto the motorcycle and speeding away," police said. "The nature of this crime appears to be both targeted and premeditated."

Political assassinations are unusual in Kenya, a relatively stable country in a region that has experienced several civil conflicts in recent years.

Were was a member of the opposition ODM party led by veteran politician Raila Odinga, who lost to William Ruto in the last election in 2022.

"Were is no more; mercilessly and in cold blood, gunned down by an assassin in Nairobi this evening," Odinga wrote on X.

Odinga rejected the 2022 election result, alleging irregularities, but Odinga and some of his allies have since struck agreements to work with Ruto to address Kenya's economic and political challenges.