Atleast seven persons were arrested in Colombo on Saturday during search operations following the assassination of Foreign Minister Lakshman Kadirgamar, a senior army commander said.
Five men travelling in a van and two others were taken into custody separately as they were unable to prove their identity, he said.
Sri Lanka's foreign minister shot dead
The Army commander said they had no direct evidence to link the men to the last night's assassination of Kadirgamar, but they were being questioned to establish their identities.
President Chandrika Kumaratunga declared a state of Emergency on Saturday, giving sweeping powers to the security forces to arrest and detain suspects. Police and troops were conducting search operations for two snipers, who are believed to have carried out the assassination.