Police are investigating whether or not a grenade attack at a bar in the western Malaysian town of Puchong was the work of ISIS sympathizers.

Early Tuesday morning local time, a hand grenade was lobbed at Movida Kitchen, Bar and Club Lounge in Puchong, where a crowd had gathered to watch a Euro 2016 soccer match, according to the Star, a Malaysian newspaper. The attack, which left eight wounded, was initially reported to have been an act of business revenge.

However, that theory is now under scrutiny after the bar’s owner, Roger Hew, said that he enjoyed good relations with other business operators in the area.

Meanwhile, one man pledging allegiance to ISIS has claimed responsibility for the attack on Facebook. In his post, he said he was seeking retribution for social activities carried out during the holy period of Ramadan, the Malay Mail reported.

“We are working closely with the state criminal investigation department to verify these claims,” an officer at the Malaysian Special Branch, the country’s intelligence agency, told the Mail.

There have been fears of a growing extremist presence in the region since jihadist attackers detonated explosives and opened fire in the Indonesian capital Jakarta in January, leaving seven dead.

Sidney Jones, the director for the Institute for Policy Analysis of Conflict in Jakarta, says that if the Malaysian attack was linked to extremists, it would “be an indication that ISIS in the region was committed to violence.”

“I don’t know yet if it was real, but it was the first time we’ve seen a claim in the name of ISIS Malaysia,” Jones tells TIME.

Get The Brief. Sign up to receive the top stories you need to know right now. Please enter a valid email address. Sign Up Now Check the box if you do not wish to receive promotional offers via email from TIME. You can unsubscribe at any time. By signing up you are agreeing to our Terms of Use and Privacy Policy . This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply. Thank you! For your security, we've sent a confirmation email to the address you entered. Click the link to confirm your subscription and begin receiving our newsletters. If you don't get the confirmation within 10 minutes, please check your spam folder.

Contact us at letters@time.com.