Philippine President Rodrigo Duterte on Friday refused to apologise for calling the US ambassador “gay” and “the son of a whore” in remarks that sparked a diplomatic row. The State Department had summoned the Philippine charge d’affaires on Monday to explain why Duterte last week ridiculed ambassador Philip Goldberg in a speech before soldiers. The US embassy on Friday reiterated that Duterte’s remarks were “inappropriate and unacceptable”. But the president was defiant, insisting: “I will not apologise for anything. He did not apologise to me when we saw each other. Why should I apologise to him?” Duterte told reporters that Goldberg started the dispute, recalling that during the campaign for May elections, the ambassador criticised him for joking about raping an Australian missionary who was sexually assaulted and murdered in a 1989 prison riot in Davao, the city he ran for two decades. “Who would not get angry at him? It was election time and he said something like that?” Duterte said Friday during a sortie to a military camp on the strife-torn southern island of Jolo. I will not apologise for anything. He did not apologise to me when we saw each other. Why should I apologise to him? Philippine President Rodrigo Duterte The US embassy warned that aid to the Philippines was tied to respect for human rights as Duterte waged a bloody war on crime that has prompted human rights groups to accuse him of tolerating extrajudicial killings. The US embassy statement came as Philippine police confirmed that they had killed 550 drug suspects since Duterte’s election. Top broadcaster ABS-CBN though said that almost a thousand people have been killed in anti-drug incidents, including almost 400 slain by shadowy vigilantes. Duterte openly boasts that he has issued “shoot-to-kill” orders to police to deal with drug suspects. The embassy said that while the United States had recently provided US$32 million in aid to the Philippines for law enforcement, the funding was conditional. “All of our security assistance promotes human rights through training content and by promoting professionalism, due process, and the rule of law,” the embassy said. It added the US-Philippine partnership was “based on a shared respect for rule of law”. Duterte has stepped up his anti-crime campaign, publicly accusing judges and officials of involvement in drugs and even threatened to impose martial law after the country’s top judge questioned his methods. Duterte’s spokesmen later said his threat was just “rhetorical”. The United States is the main defence ally and former colonial ruler of the Philippines, which is fighting domestic insurgencies while embroiled in a maritime dispute with Beijing over the South China Sea.