Police have declared war on the gangs responsible for four Sydney shootings in as many days. And any would-be vigilantes and copycats have also been warned to butt out. Sydney's western suburbs came under siege again on Thursday about 12.30am (AEDT) when shots rang out in Bankstown Witnesses told police they saw a man wielding a rifle in a neighbourhood where a bullet hit a bedroom window in a home. A woman and her four children, aged between two months and 10, were in the room but no one was injured. Acting Commissioner Nick Kaldas labelled as cowards the people responsible for a string of shootings since Monday. "A lot of the conflicts that occur between these criminal groups is drug-related, unfortunately," Mr Kaldas told reporters on Thursday. "It's a combination of many ethnic-based groups as well as criminal types." Police launched Operation Spartan on Thursday and will deploy extra resources to the affected suburbs from the Public Order and Riot Squad, Dog Squad, Gangs Squad and the Middle Eastern Organised Crime Squad. Gangs Squad head Arthur Katsogiannis said the nature of the crimes was keeping vital information from getting to police. "Our frustration as investigators and police officers on the front line is the lack of assistance we're getting from both the victims and the witnesses," Superintendent Katsogiannis said at the same media conference. Police also warned would-be vigilantes and others to stay away. "One thing I hope that doesn't occur is any sort of copycat attraction," Mr Kaldas said. "Others may feel they want to take the law into their own hands. And my advice to those people is all you'll simply do is turn yourself from a victim into an offender." Mr Kaldas denied suggestions that gun crime was on the increase and said the incidents since Monday were a "spike" in shooting crimes. Around 2am (AEDT) on Wednesday the occupants of two cars were involved in a gun battle in Greenfield Park, in western Sydney. On Monday night, two drive-by attacks occurred in Auburn and Arncliffe, in Sydney's west and south respectively. Around 25 people were inside the two homes when the properties were sprayed with up to 35 bullets. Police are confident they will make arrests over some of the shootings. Asked if the shootings were all related, Mr Kaldas replied, "I have to say the bulk of them are not." NSW opposition emergency spokesman Nathan Rees said tweaking tough anti-bikie laws would be one way to help put an end to "gang warfare". As premier in the former Labor government, Mr Rees gave the Supreme Court powers to outlaw bikie gangs and prevent members from contacting each other. But the Crimes (Criminal Organisation Control) Act was struck out in June 2011 after Sydney Hells Angel Derek Wainohu challenged it in the High Court. The National Coalition for Gun Control has called on NSW Premier Barry O'Farrell and the government to strengthen gun control laws. Police seized 6155 guns in the 2010/11 financial year and have seized 3663 guns in the first half of the current financial year. Most guns used in crimes are stolen from legitimate sources.