US President Donald Trump’s son-in-law and senior advisor Jared Kushner is facing investigation for contact with senior Israeli officials in an attempt to block a UN resolution condemning Israel’s occupation, the Washington Post reported yesterday.

Robert Mueller, the special counsel investigating Russia’s interference in the 2016 US presidential elections, is reportedly looking into efforts made by Kushner during the transition period between the Obama and Trump administrations at the end of 2016.

The paper claimed that several sources involved in the investigation said that Kushner had spoken with senior Israeli officials who sought to thwart a UN Security Council’s resolution which condemned Israel’s occupying activities in East Jerusalem and the West Bank as illegal under international law.

If true, the cooperation would be one of many allegations of conversations between Kushner and foreign leaders during the two month transition period between the November election and the time that Trump took office.

Read: Kushner secretly visited Saudi Arabia, Israel for peace efforts

Former President Barack Obama had caused controversy when he chose to abstain from the vote, rather than veto the bill in December. Israeli officials subsequently turned to Donald Trump, requesting he pressure other countries to block the bill. At one point it was believed that Russia may have vetoed the bill, although it eventually voted in favour of the motion.

Kushner is also currently under scrutiny by the FBI for undisclosed contacts with the Russian ambassador to the United States during and after the 2016 presidential campaign.

Since the inauguration of Trump, Kushner has been charged with spearheading the Middle East peace process. However, a recent report in Politico found that despite carrying information on and conducting some of the country’s most sensitive diplomatic talks, Kushner does not have sufficient security clearance.

Kushner is a strong advocate of Israel and his support for the country, say critics, is odd even by American standards. He has given money to Israeli settlements and his family are close friends of Israeli Prime Minister Benjamin Netanyahu.

Read: Greenblatt: No Israel-Palestine peace talks in sight