US President Barack Obama urged Philippine leader Rodrigo Duterte on Thursday to conduct his crime war "the right way," after 3,000 people were killed in the crackdown in just over two months. "As despicable as these (crime) networks may be and as much damage as they do, it is important from our perspective to make sure that we do it the right way," Obama said when asked about his conversation with Duterte on the sidelines of a regional summit in Laos. "Because the consequences of when you do it the wrong way are innocent people get hurt and you have a bunch of unintended consequences that don't solve the problem." Relations between long time allies the US and the Philippines saw a spectacular setback this week after firebrand politician Duterte used an expletive for Obama. The outburst on Monday was in response to being told Obama planned to raise concerns about his war of drugs. "You must be respectful. Do not just throw away questions and statements. I will curse you in that forum," Duterte said shortly before flying to Laos. "We will be wallowing in the mud like pigs if you do that to me." At the press conference marking the end of his trip to Laos Obama said he was unfazed by Duterte's jibe. "I don't take these comments personally because it seems as if this is a phrase he's used repeatedly including directed at the pope and others," adding that such choice words were "a habit, a way of speaking for him." However Obama cancelled a meeting with Duterte scheduled for Tuesday because of the outburst. They met briefly on Wednesday night before a leaders' dinner, but only exchanged "pleasantries," according to the White House. Duterte was elected to office in a landslide this year after pledging to kill 100,000 people in an unprecedented war on crime. He vowed in the campaign that so many bodies would be dumped in Manila Bay that the fish there would grow fat from feeding on them. Duterte has also repeatedly promised to protect police from prosecution if they are charged over the deaths and insisted human rights cannot get in the way of his war. Duterte has said the Philippines is in danger of becoming a "narco state," and eliminating drugs in society is the top priority of his administrations. On the day he was sworn into office, June 30, Duterte urged people living in a Manila slum to kill drug addicts in their community. His handpicked police chief, Ronald dela Rosa, last month called for drug addicts to kill traffickers and burn down their homes. The United Nations special rapporteur on summary executions has warned incitement to kill is a crime under international law. Despite growing condemnation of the comments and what rights groups say are rampant extrajudicial killings, Duterte has vowed to continue. "More people will be killed, plenty will be killed until the last pusher is out of the streets," Duterte said on Monday.