Former Trump campaign foreign policy adviser George Papadopoulos has requested the Senate Intelligence Committee grant him immunity before he appears before the panel, according to a new report.

Papadopoulos, who testified before the House Judiciary and Oversight Committees earlier this week, is asking for immunity from the Senate panel before deciding if he will testify before them, CNN reports.

The committee may subpoena him if he refuses to appear of his own volition, although he could then invoke his Fifth Amendment right and not respond to questions.

Papadopoulos did not have immunity from the House when he voluntarily testified before the House committees, which is examining how the Justice Department and the FBI managed probes examining former Secretary of State Hillary Clinton and Russia.

However, the Senate is homing in on Russian interference in the 2016 election, and whether the Trump campaign colluded with the Kremlin.

Papadopoulos pleaded guilty last year to misleading FBI agents concerning his contacts with Russians. He said in his guilty plea he would comply with special counsel Robert Mueller’s team and “provide information regarding any and all matters as to which the government deems relevant.”

Mueller is also examining Russian interference and potential collusion with the Trump campaign. He also is looking at whether President Trump obstructed justice by firing former FBI Director James Comey.