"The purpose is to get information as to what (former army chief) Sarath Fonseka's officials planned by detaining them within the hotel rooms," the government's website quoted defence sources as saying.

Authorities are already interrogating army "deserters" over the alleged coup plot by Fonseka, who was trounced by Rajapaksa in the January 26 Presidential poll.

Several media persons were present at the hotel, where Fonseka had moved in a day after the polls.

"Comprehensive inquiries are already in progress on the alleged plan mooted by the Sarath Fonseka group to assassinate President Mahinda Rajapaksa with the announcement of the Presidential election results (on January 27)," the website said.

Fonseka and his supporters were staying in more than 70 rooms of the hotel from where army deserters carrying weapons were arrested, it said, adding that those held were still under interrogation.

According to investigators, the recovery of explosives from some areas before the Presidential polls is linked to the President's assassination plot, the government website said.