CRIMES committed by mainland illegal immigrants have soared, police say, with a 75 per cent rise in arrests compared to last year. Overall, 998 illegal immigrants were detained between January and September, compared to 571 during the same period last year. This excluded immigration offences, which fell. Violent crime was up 10 per cent, with 179 arrests. Of particular concern to police is that the crime wave has come when the arrival of illegal immigrants is down 15 per cent to 19,804 cases from 23,425 last year. Matters were, not surprisingly, worse in border areas. Figures for the northern New Territories show overall offences up by 68.8 per cent to 319 arrests, with cases of violent crime rising by 60 per cent to 92. The news came soon after Police Commissioner Eddie Hui Ki-on briefed Governor Chris Patten on concerns over the surge in immigrant crime. The availability of weapons and the rise in their use by illegals is believed to have been discussed. Of major interest to officers is the origin of illegal immigrants, with the northern provinces of Jiangsu and Zhejiang topping the list. Police sources say this suggests an organised illegal immigration racket. Earlier this year, police blamed a nine per cent crime rise on illegal immigrants and a surge in two-way permit holders engaging in 'crime holidays'.