Colombo: On Friday, the Sri Lankan police arrested five suspects, who allegedly have links with local Islamist group National Thowheed Jamaath (NTJ) and its leader Zahran Cassim - believed to be the mastermind behind the Easter Sunday bombings.

The five suspects were arrested in Horowpathana area on the day when the Parliament passed the state of emergency with 22 lawmakers voting for it, and eight Tamil National Alliance members voting against it.

Sri Lankan President Maithripala Sirisena extended the state of emergency imposed in the wake of the deadly Easter Sunday bombings, by a month. The emergency law gives police and military, extensive powers to arrest, detain and interrogate suspects without court orders.

The five that have been arrested include a development officer attached to the Horowpathana Divisional Secretariat, a teacher of a government school in Horowpathana, two teachers of an Arab school in Kiwulekada and a resident of Kebithigollewa, said news reports.

According to the police, the suspects had delivered extremist sermons upon the invitation of suicide bomber Zahran in the Horowpathana, Kebithigollewa and Trincomalee areas.

Investigations have shown that the arrested suspects were closely associated with another suspect, who has been arrested overseas. Police said investigations revealed that the five suspects had received funds from the NTJ via one of the main suspects in the Easter Sunday attacks, who is abroad.

Zahran was one of the two suicide bombers at the Shangri-La Hotel on April 21. He was killed inside the luxury hotel where he blew himself up.

Nine suicide bombers carried out a series of devastating blasts that tore through three churches and as many luxury hotels on April 21, killing nearly 260 people and injuring 500 others.