KUALA LUMPUR • Malaysian police yesterday said that a grenade attack on a nightspot last week was carried out by men connected to the Islamic State in Iraq and Syria (ISIS) terrorist group, making the blast its first successful attack in the country.

The attack at the Movida restaurant-bar at 2.15am last Tuesday injured eight Malaysian patrons.

Police have arrested 15 Malaysians in a counter-terrorism swoop after the attack. The club is located in Puchong in Selangor state, some 25km from Kuala Lumpur.

Malaysia's police chief Khalid Abu Bakar said those nabbed included two men directly linked to the attack, and that they received direct instructions from Muhammad Wanndy Mohamed Jedi, a known Malaysian ISIS fighter. Muhammad Wanndy is believed to be in Syria.

"There were elements of IS involvement in the attack," Tan Sri Khalid, the Inspector-General of Police, said at a news conference, referring to the militant group as the Islamic State.

The duo who were detained had been "commanded" to carry out attacks in Malaysia, "on our government leaders, top police officials and judges", he said.

"These three groups are considered as threatening to IS activities," Mr Khalid added. Police are hunting for two more men believed to be directly involved in the attack.

Police had last Tuesday ruled out terrorism as a motive for the pre-dawn attack.

Investigators initially said that a business rivalry, or a targeted attack on someone in the bar, were the more likely motives.

But they were forced to reassess their position a day later after an ISIS claim of responsibility was posted on Facebook.

Mr Khalid said police also arrested 13 others, including two low-ranking police officers, in the counter-terrorism crackdown.

He said those detained had all received instructions to carry out attacks on top officials "and also entertainment centres, which they consider un-Islamic".

The ISIS terrorist group two weeks ago released a video of its fighters from South-east Asia calling on its supporters to stay home and to launch attacks in the region.

Malaysia practises a moderate brand of Islam and has not seen any notable terror attacks.

But concern has risen in the multi-faith nation, with the authorities saying scores of Malaysians had gone to join ISIS. The country's political opposition says the government shrouds its anti-terror fight in secrecy, making it difficult to gauge the actual threat level.

Malaysian police have regularly announced ISIS-related arrests but typically offer few details.

Four suspected militants were arrested in January, and in April last year, 17 people were arrested on suspicion of plotting terror attacks in Kuala Lumpur.

In 2014, police said they had foiled an ISIS-inspired plot to bomb pubs, discos and a Malaysian brewery of Danish beer producer Carlsberg, arresting more than a dozen people.

REUTERS, AGENCE FRANCE-PRESSE