US President Donald Trump has said he found Saudi Arabia's explanation about the death of dissident journalist Jamal Khashoggi credible and termed it an "important first step."Trump added if the US takes action, he does not want it to impact arms sales to the kingdom, which said Khashoggi was killed in a fight at its Istanbul consulate. Turkish officials pointed to a state-sanctioned hit."I do, I do," Trump said when asked if he found the Saudis' explanation credible, adding: "It's early, we haven't finished our review or investigation, but... I think it's a very important first step.""I would prefer, if there is going to be some form of sanction or what we may determine to do, if anything... that we don't use as retribution cancelling $110 billion worth of work, which means 600 000 jobs," he said during a visit to Arizona, referring to a major arms deal with the kingdom.Trump has sent mixed messages about Khashoggi for days, vowing a severe response but also saying that the United States wants to preserve its close relationship with the conservative kingdom.Members of the US Congress were far harsher in the wake of the kingdom's admission that Khashoggi was dead.Republican Senator Bob Corker, Senate Foreign Relations Committee chairman, said he doubted the credibility of the Saudi authorities, who insisted for weeks that he left the consulate."The story the Saudis have told about Jamal Khashoggi's disappearance continues to change with each passing day, so we should not assume their latest story holds water," he tweeted.Senator Lindsey Graham, a close Trump ally who has nonetheless been outspoken about Khashoggi, shared Corker's suspicion."To say that I am skeptical of the new Saudi narrative about Mr Khashoggi is an understatement," the Republican senator tweeted. Targeting Saudi officials Bob Menendez, the top Democrat on the Senate Foreign Relations Committee, said the United States should pursue sanctions against Saudis involved in Khashoggi's death under a US law named after Sergei Magnitsky, the anti-corruption Russian accountant who died in custody. "The Global Magnitsky Act doesn't have exceptions for accidents. Even if Khashoggi died because of an altercation, that's no excuse for his murder," Menendez tweeted. "This is far from the end and we need to keep up the international pressure." Khashoggi, a Washington Post contributor who lived in suburban Washington, was a former insider who turned into a critic of the kingdom's direction under Crown Prince Mohammed bin Salman.He visited the Saudi consulate in Istanbul on October 2 to sort out marriage paperwork, but his fiancee saw nothing more of him after he entered.Representative Mike Coffman, one of a number of lawmakers from Trump's Republican Party facing a tough race in November 6 elections, said the United States "must stand up for our values and demand our 'allies' respect human rights."The Colorado lawmaker, who serves on the House Armed Services Committee, urged Trump to immediately recall the acting US ambassador from Saudi Arabia. Trump has yet to nominate a permanent envoy to the kingdom.United Nations chief Antonio Guterres meanwhile demanded that those responsible for Khashoggi's death be held to account."The Secretary-General is deeply troubled by the confirmation of the death of Jamal Khashoggi. He extends his condolences to Mr Khashoggi's family and friends," Guterres's office said in a statement. "The Secretary-General stresses the need for a prompt, thorough and transparent investigation into the circumstances of Mr Khashoggi's death and full accountability for those responsible."