Malaysia's police chief said on Monday that 17 people, including two who recently returned from Syria, had been arrested on suspicion of plotting terror attacks in the capital Kuala Lumpur.
Authorities in the Muslim-majority country have expressed increasing alarm over the threat of Muslim militancy in the wake of the Islamic State (IS) group's bloody jihad in Syria and Iraq.
"Seventeen people were planning terror activities in Kuala Lumpur. Two of them had recently returned from Syria," national police chief Khalid Abu Bakar said in a Twitter posting.
Khalid said the arrests took place Sunday. No other details, such as the suspects' nationalities or specifics on what they had been plotting, were mentioned.
AFP was not immediately able to reach anti-terrorism officials for comment.
Malaysia has traditionally observed a moderate form of Islam, and authorities have kept a tight lid on militancy.
But the government has increasingly warned that Malaysian recruits to the IS cause could return home with the group's radical ideology.
Police said in January they had arrested a total of 120 people with suspected IS links or sympathies, or who were detained as they sought to travel to Syria or Iraq.
They also said 67 Malaysians were known at the time to have gone to abroad to join IS, and that five had died fighting in the group's jihad.
Last week, the government introduced new anti-terrorism legislation to counter the potential IS threat.
The bill, which has come under fire from rights groups, allows authorities to detain terrorism suspects for potentially unlimited periods without trial, according to its critics.