Democratic congressional leaders Rep. Nancy Pelosi and Sen. Chuck Schumer on Wednesday urged the FBI and Justice Department to include top lawmakers from both parties at a highly sensitive meeting about the Russia investigation, instead of the two House Republicans the White House invited.

This meeting is completely improper in its proposed form and would set a damaging precedent for our institutions and the rule of law.

— Pelosi and Schumer wrote in a letter to Deputy Attorney General Rod Rosenstein and FBI Director Christopher Wray

The details: House Intelligence Committee Chairman Rep. Devin Nunes (R-Calif.) and House Oversight Committee Chairman Rep. Trey Gowdy (R-SC) will meet with top intelligence and law enforcement officials to discuss classified intel related to an F.B.I. informant who contacted members of the Trump campaign in the early days of the Russia probe.

As Axios' David Nather notes, it's now clear from multiple reports that the FBI had an informant who talked to two campaign advisers, but not that the informant was planted on the inside.

The other side: White House Press Secretary Sarah Sanders said Tuesday that Democrats will not attend the meeting coordinated by White House Chief of Staff John Kelly because "my understanding is they haven't been the ones requesting this information."

Go deeper: Read the letter Pelosi's and Schumer's joint letter here