Air force sends an investigative team to establish cause of crash that killed General Francis Ogolla.
General Francis Ogolla and nine other people were killed in the crash at 2:20 pm (11:20 GMT) on Thursday in Elgeyo Marakwet County, about 400km (250 miles) northwest of the capital, Nairobi.
The military aircraft had been on a visit to troops deployed in northwest Kenya to combat cattle rustling and came down just minutes after taking off near Cheptulel Boys Secondary School in West Pokot County.
It was not immediately clear what caused the crash.
“Our motherland has lost one of her most valiant generals,” Ruto said at a news conference. “The demise of General Ogolla is a painful loss to me.”
Two soldiers survived the crash and were in hospital, the president said, adding that an air investigation team had been sent to find out the cause of the incident.
Ogolla was previously the head of the Kenyan air force before rising to deputy military chief and then being promoted by Ruto last year to head the military.
The general joined the military in 1984 and trained as a fighter pilot with United States air force and as an instructor pilot at the Kenyan air force, according to a Ministry of Defence profile.
When promoting Ogolla to the top military job a year ago, Ruto accused him of being part of a plot to overturn the result of the 2022 presidential election but said he was the best qualified person for the job.
Dozens of civilians and police officers have been killed in the unrest in northwestern Kenya.
At least 10 soldiers were killed in June 2021 when their helicopter crashed while landing near Nairobi.