Australian police Wednesday said they fired tear gas, sound and flash weapons and \"bean bag\" bullets to quell overnight riots at the Christmas Island immigration detention centre. Immigration authorities said about 50 detainees were involved in the disturbance, which saw fires lit and police threatened with makeshift weapons at the centre, some 2,600 kilometres (1,600 miles) from Australia\'s mainland. \"(Police) members made a number of attempts to defuse and de-escalate the situation, but these were not successful,\" a police spokeswoman told AFP. \"AFP members had cause to deploy a range of use of force options, including less-lethal munitions (such as) bean bag rounds, (tear) gas, and sound and flash distraction devices.\" \"Bean bag\" bullets are small cushions filled with lead shot that are fired from a shotgun, designed to temporarily disable targets. It is the second time in as many months serious riots have rocked the remote centre, which is the cornerstone of Australia\'s mandatory detention policy for refugees and home to more than 1,100 boat arrivals. Some of the group escaped their compounds but an immigration spokesman said there was \"no breach of the perimeter fence\" and police had brought the incident under control without injury to detainees or staff. One detainee was arrested and another was still staging a rooftop protest. Police remained on site, the spokesman added. Australia\'s immigration facilities are under strain from a record influx of boatpeople last year -- almost 6,900 -- and tensions have run high in crowded centres on both Christmas Island and at Villawood, in Sydney. Up to 100 detainees rioted on the Indian Ocean island last month, and another 250 were involved in violent protests there in March over the slow processing of asylum claims, with some locked up for 18 months or more. Nine buildings were torched in wild riots the following month at Villawood that involved up to 100 detainees. Australia\'s mandatory detention policy has been criticised by human rights groups and the UN\'s refugee agency, with depression and suicide major concerns. Refugees are a thorny issue in Australia, despite their relatively small numbers and the fact that many who arrive in leaky boats from Asia have fled strife in Afghanistan, Sri Lanka and Iraq.