The Trump administration twice approved licenses for the export of nuclear technology to Saudi Arabia after the murder of the Washington Post columnist Jamal Khashoggi, it emerged on Tuesday.

In response to repeated requests, the US Department of Energy informed the Senate on Tuesday that, of a total of seven permits for nuclear technical expertise transfers to Riyadh, one was approved on 18 October last year – 16 days after Khashoggi’s murder and dismemberment in the Saudi consulate in Istanbul. The most recent approval was dated 18 February this year.

The Democratic senator Tim Kaine said: “I have serious questions about whether any decisions on nuclear transfers were made based on the Trump family’s financial ties rather than the interests of the American people.”

Trump and his secretary of state, Mike Pompeo, have ignored US intelligence findings that the Saudi crown prince, Mohammed bin Salman, almost certainly ordered the killing of Khashoggi. Trump and Pompeo have continued to treat the crown prince as a close ally.

The administration refused to comply with a congressional demand that it reach a determination about the Saudi government’s responsibility for the murder of the Saudi dissident who had been a US resident before he was killed. It also bypassed Congress to approve “emergency” sales of arms to Saudi Arabia.

Senator Kaine said in a written statement: “Trump’s eagerness to give the Saudis anything they want, over bipartisan congressional objection, harms American national security interests and is one of many steps the administration is taking that is fueling a dangerous escalation of tension in the region.”

The nuclear technology export permits are known as part 810 authorisations. They allow transfer of knowhow but not equipment. However, the administration’s critics suspect the administration of using them to evade non-proliferation restrictions that are normally imposed on US nuclear sales, which require the purchaser to agree not to enrich uranium or reprocess plutonium that could be used in weapons.

The Saudi government is close to completion of a small research reactor in Riyadh but has much greater ambitions for its nuclear programme, and is reluctant to accept non-proliferation restraints.