Police are investigating 30 people for suspected involvement in a public assembly without a police permit.

In a statement yesterday, police said the group members, aged between 21 and 56, had gathered at Sembawang Park on Saturday for an event in support of the bull- taming practice Jallikattu.

Some of them had placards, and preliminary investigation indicated they were there to show support for Jallikattu and for ongoing protests in India against the banning of the sport last year.

Jallikattu is typically practised in Tamil Nadu in India as part of the festivities during Pongal, a harvest festival celebrated around January. Bulls are let loose in an open field and young men compete to subdue them bare-handed.

It was banned in India last year over animal welfare concerns, but the ban was reportedly revoked on Saturday after days of protests.

The investigations here follow a police statement last week reminding the public of the laws regarding public assembly. This was after the police came to know of plans to hold a Jallikattu-related event here.

Police reminded the public yesterday that it is illegal to organise or participate in a public assembly without a permit.

"Foreigners visiting or living in Singapore have to abide by our laws. They should not import the politics of their own countries into Singapore.

"Those who break the law will be dealt with firmly, and this may include the termination of visas or work passes, where applicable," said the police.