A decreasing number of Americans approve of President Trump’s handling of the investigation into Russian interference in the 2016 election, according to a poll released Tuesday.

A CNN poll found that 29 percent of adults approve of how Trump has conducted himself surrounding the investigation, down from 33 percent in October.

The president’s approval dipped with members of both major parties, the poll found. Fifty-one percent of Republicans approve of his handling of the probe, while just 15 percent of Democrats give him positive marks.

{mosads}The poll also found that special counsel Robert Mueller’s approval has dipped slightly. Forty-three percent of adults approve of the special counsel’s handling of the investigation, down from 48 percent in October.

Mueller’s approval is split along partisan lines. Among Democrats, 71 percent approve of the special counsel’s handling of the investigation, compared to 21 percent of Republicans. 

The poll surveyed 1,015 people from Dec. 6 to 9 and has a margin of error of 3.8 percentage points. 

The survey was conducted during the same week that Mueller filed additional court papers pertaining to the investigation.

In a filing last Wednesday, Mueller’s team laid out the extent of cooperation between prosecutors and Trump’s former national security adviser Michael Flynn.

On Friday, Mueller’s team detailed allegations that former Trump campaign chairman Paul Manafort lied to prosecutors after reaching a plea deal.

The special counsel also filed supplementary paperwork about former Trump attorney Michael Cohen, who prosecutors in Manhattan said on Friday violated campaign finance law at the president’s direction.

Trump has decried the special counsel’s investigation as biased and has called it a “witch hunt.” He has repeatedly insisted he did not collude with Russia during the 2016 presidential race.

Mueller’s investigation has thus far implicated five former Trump associates and more than 20 Russian nationals.