Mark Walker, a member of the House GOP leadership team, said Thursday that Michigan Rep. Justin Amash should be stripped of his committee seats now that he is leaving the Republican Party. Amash announced his departure in a Washington Post op-ed Thursday.

"Amash left the @freedomcaucus now he’s leaving the @GOP. The @HouseGOP never left @justinamash - we simply ran out of space for his ego. However, we should make sure he leaves Conference and his committee," Walker tweeted Thursday. Walker is vice chairman of the House Republican Conference, which sets party policy.

Amash left the @freedomcaucus now he’s leaving the @GOP. The @HouseGOP never left @justinamash - we simply ran out of space for his ego. However, we should make sure he leaves Conference and his committee. — Rep. Mark Walker (@RepMarkWalker) July 4, 2019

Amash holds a seat on the House Government Reform and Oversight Committee, which has investigative powers over government activities. He serves on its subcommittees for civil rights and national security.

Amash wrote in an op-ed Thursday, "Today, I am declaring my independence and leaving the Republican Party." He said he had become "disenchanted with party politics and frightened by what I see from it. The two-party system has evolved into an existential threat to American principles and institutions." He has called for President Trump's impeachment.