A Kenyan member of parliament who was allegedly abducted by unknown men after a church service on Sunday is being treated in hospital after being found on a coffee farm, former Deputy President Rigathi Gachagua has said.

George Koimburi had been "badly beaten" and was in a "very serious condition" at the Karen Hospital in the capital Nairobi, Gachagua added.

A vocal critic of the government, Koimburi is allied with Gachagua, who was impeached by parliament and removed from office last year after falling-out with President William Ruto.

The alleged abduction has sparked outrage, with the opposition accusing the government of intimidation. It has not yet commented on the allegation.

Police said they were investigating the incident, local media reported.

A motorcycle rider who first found Koimburi early on Monday morning is said to have alerted other people and his family, the reports added added.

A widely shared video clip showed the MP lying on the ground, his clothes dishevelled and seemingly in pain.

On Sunday, Koimburi's wife told reporters that they were outside church, in his Juja constituency in central Kiambu county, when he was grabbed and bundled into a vehicle.

Koimburi was reportedly found at a coffee farm in the nearby Ruiru constituency, less than 10km (six miles) from where he had been allegedly abducted.

Speaking after visiting him in hospital, Gachagua accused the government of targeting legislators who took a "vocal stand against the government".

There has been a wave of abductions in Kenya since mass protests against tax hikes broke out last year. The government has previously denied involvement in the kidnappings.

Prominent opposition politician Kalonzo Musyoka said that opposition officials would meet on Tuesday to "assess the current state of political harassment and intimidation in the country by the Kenya Kwanza [governing] regime".

He raised concerns over how an MP, who was entitled to security by the police, could "get abducted in broad daylight".

"It means Kenyans are on their own," Musyoka added.

In February, Koimburi was arrested and charged with forging his academic qualifications. He denied the charge and was released on bail.

Police are reported to be also investigating him over allegations of land fraud and misuse of government funds. He denies any wrongdoing.

His alleged abduction came weeks after MP Charles Ong'ondo Were was shot dead in the streets of Nairobi by gunmen on a motorcycle.

Police said several suspects had been arrested following what appeared to be a "targeted and predetermined" assassination.

Many Kenyans are alarmed by the deteriorating security situation.

The Kenya National Commission on Human Rights says that more than 80 people have been abducted since mass protests broke out last June against an increase in taxation, in what was the biggest challenge to the authority of Ruto's government since it took office in 2022.

The commission blamed the abductions on state security agencies, but they denied any involvement.

Earlier this month, Ruto said the government had taken action to prevent further abductions, but did not give details.