All their tombstones were broken or forcibly dislodged and scattered when The Straits Times visited the cemetery, where about 30 members of the small Ahmadiyya community are buried, yesterday.

Police said a report has been made and it is investigating the incident.

The National Environment Agency, which manages cemeteries, said its staff noticed the damage around 3pm on Sunday in the course of routine maintenance, made a police report and called the Ahmadiyya community's leader, Mr Abdul Halim Mohd Yusoff.

Technician Abdul Latif Mohamed, 50, whose father is buried there, said the grave of his father, who died in 2004, was the most badly damaged.

'We had retiled it only months ago. I'm very disappointed. We'll leave it to the police to investigate, but such acts are worrying,' said Mr Abdul Latif.

The community, which has been here since the early 20th century, is about 220-strong.

Although the Ahmadis worship as Muslims do, Islamic authorities here and in many countries do not recognise them as Muslims.

Ahmadis believe that Mirza Ghulam Ahmad, who founded their movement in Qadian in the Punjab in 1889, was the messiah. However, the Muslim authorities say this goes against Islamic beliefs that Prophet Muhammad is the last prophet.

In recent years, Ahmadis in such places as Indonesia and Pakistan have been attacked by mobs. This month, the Indonesian government decided not to ban the sect despite pressure from conservative Muslim groups.

In Singapore, the group has had a largely trouble-free relationship with the Muslim community, even though several members say they have occasionally been abused verbally.

Members did not want to speculate on who might be behind the incident, the first on such a scale here, and said they would prefer to let the investigation take its course.

Mr Abdul Halim, 39, president of the Ahmadiyya Muslim Mission, said: 'We hope this will not happen again.'

Muslim leaders had strong words for those who committed the act, but noted that the identity of the perpetrators has yet to be established.

Said Khadijah Mosque chairman Ustaz Ali Haji Mohamed: 'Such actions are not right, they are not civilised. No religion will condone such things.'