Deputy Attorney General Rod Rosenstein will testify next week before the House Judiciary Committee about special counsel Robert Mueller's investigation into possible collusion between the Trump campaign and Russia.

Rosenstein will appear before the panel on Dec. 13, Judiciary Committee Chairman Bob Goodlatte (R-Va.) announced Wednesday.

Rosenstein's hearing comes as Republicans express concerns over possible bias in Mueller's investigation. Reports last week said the special counsel had removed a veteran FBI agent from his team for sending anti-Trump text messages.

It was later reported the same agent, Peter Strzok, edited a key phrase in former FBI Director James Comey's statement about his decision on the Hillary Clinton email investigation.

Goodlatte said committee members will have the chance to question Rosenstein about those developments.

Rosenstein said in an interview published Wednesday with an NBC affiliate in Maryland that he is satisfied with Mueller's work so far.

Rosenstein appointed the special counsel in May after Attorney General Jeff Sessions recused himself from matters involving Russian election meddling.

Mueller has issued indictments or received guilty pleas from four former Trump campaign associates.

Last week, former national security adviser Michael Flynn pleaded guilty to lying to FBI agents. As part of the plea agreement, Flynn has agreed to cooperate fully with the investigation.

A campaign aide, George Papadopoulos, has also pleaded guilty to lying to investigators and is cooperating with Mueller's team.

Two other campaign officials, former campaign chairman Paul Manafort and his associate Richard Gates, also face charges in the investigation. They have both pleaded not guilty.

The House Judiciary Committee is one of several congressional committees conducting separate investigations into Russian interference in the 2016 presidential election.