All Indian prisoners are safe in the Welikada prison in Sri Lanka where a major riot broke in which at least 27 inmates were killed and 42 others injured.

India's High Commission in Sri Lanka has been closely monitoring the evolving situation in the Welikada prison since last evening, official spokesperson in the Ministry of External Affairs said on Saturday.

He said High Commissioner Ashok Kantha has been in touch with Defence Secretary Gotabaya Rajapaksa and Foreign Secretary Amunugama.

"He was assured that the situation is under control and all Indian prisoners are safe," the spokesperson said.

It is understood that there are 39 Indian prisoners in the prison among a total of 4000 inmates. These Indian prisoners include 34 who are sentenced and 5 under trials brought from Jaffna.

The High Commission officials in Colombo have been in touch with prison officials and are pressing for early consular access, the spokesperson added.

The riot started after authorities launched a search for drugs within the prison, and the inmates turned against the operatives of the police's Special Task Force (STF).