According to news portal, the suspect, 26, was arrested in the town of Balangoda. During the search, the police seized a tablet, several mobile phones, 13 SIM cards, bullets and a number of credit cards, Police also found an improvised map showing roads leading to the parliament building.
The suspect is reportedly expected to appear before a local court later in the day.
Sri Lanka remains on high alert after on Easter Sunday, the country was shaken by a series of coordinated attacks that left 359 people dead and over 500 injured nationwide. These attacks, which targeted churches and luxury hotels, were the worst the country has faced since the end of its 25-year-old civil war in 2009. Daesh* terrorist group reportedly claimed responsibility for the attacks on Tuesday.
Sri Lanka authorities launched a criminal investigation after the terrorist attacks, and have already arrested around 80 suspects.
*Daesh (also known as ISIS/ISIL/IS) is a terrorist group banned in Russia