The Senate Judiciary Committee is planning to call former Trump campaign chairman Paul Manafort as part of its investigation into whether he followed laws requiring people to register as foreign agents.

"We're working very close on this and we've already agreed that we're going to bring Manafort before our committee," Sen. Chuck Grassley, the committee's chairman, said in a press call with Iowa reporters on Wednesday.

Grassley's office later said the committee is in the process of "working with Special Counsel [Robert] Mueller" to make sure having him come before the committee "would not conflict with any criminal investigation."

"If conflicts exist, then Chairman Grassley is prepared to work with Special Counsel Mueller to find a way for the committee to proceed with its oversight responsibility," said Grassley spokesman Taylor Foy.

Peter Carr, a spokesman for Mueller's team, declined to comment.

Grassley added that Manafort's meeting with Donald Trump Jr. and Russian attorney Natalia Veselnitskaya is also on the table in light of the email chain released by the the president's son.

"If he comes before our committee – and we'll subpoena him if necessary – then … obviously it'd be appropriate for anybody to get into anything that went on at that meeting, since he was at that meeting," Grassley explained.

Manafort resigned in August amid questions over his ties to work for former Ukrainian President Victor Yanukovych. It was reported in June that as part of Mueller's investigation into Russia's interference in the 2016 election, Manafort would be included.