President Obama said Monday that Attorney General Eric Holder plans to visit Ferguson on Wednesday to meet with federal investigators and community leaders.

The Justice Department has opened a civil rights investigation into Michael Brown’s death. Holder updated Obama on Monday about the status of the investigation, which is being carried out by officials “devoting substantial resources” to the task, Obama said during a news conference at the White House Monday.

When discussing the situation in Ferguson, Obama said that while the death of Michael Brown is tragic, he cautioned that he wanted to be careful about his comments.

“I have to be very careful about not pre-judging these events before investigations are completed because although these are issues of local jurisdiction, the DOJ works for me, and when they’re conducting an investigation, I’ve got to make sure I don’t look like I’m putting my thumb on the scale one way or the other,” he said.

But while he said he couldn’t comment on any specific case beyond calling for a transparent investigation, he described “the ongoing challenge” of dealing with communities that have been left behind or feel isolated in the country.

There are protesters in Ferguson who have “legitimate grievances,” but there are also those using the tragedy as an excuse for violence and looting, he said.

Obama, who also discussed the situation in Iraq during the same news conference, called for calm and peace rather than anger and violence.

“Let’s seek to heal rather than to wound each other,” he siad.

Obama again said that while most protesters are acting peacefully, he said that those who are looting or attacking police are only raising tensions. But there is “no excuse for excessive force by police,” Obama said,

“In too many communities around the country, a gulf of mistrust exists between local residents and law enforcement,” Obama said. “In too many communities, too many young men of color are left behind and only seen as objects of fear.”