Former president Donald Trump suggested Sunday evening that he might skip a Sept. 10 ABC News debate with Vice President Kamala Harris (D), after agreeing to participate as the GOP presidential nominee earlier this month.

“I watched ABC FAKE NEWS this morning, both lightweight reporter Jonathan Carl’s (K?) ridiculous and biased interview of Tom Cotton (who was fantastic!), and their so-called Panel of Trump Haters, and I ask, why would I do the Debate against Kamala Harris on that network?” Trump asked in a social media post Sunday evening.

The Sept. 10 debate is the only one that both campaigns have officially committed to with a network. Trump’s renewed questioning of the ABC News debate comes as Harris has increased her lead in national polls and is gaining ground in key Midwestern swing states. As of Sunday, The Washington Post polling average has the vice president leading in Wisconsin by three points, in Pennsylvania by two points and in Michigan by less than one point. Trump continues to lead in the Sun Belt states, but Harris has significantly narrowed the gap.

It’s not the first time the former president has suggested he would back out of the ABC News debate. Earlier this month, Trump said that he would no longer appear at the Sept. 10 debate — previously scheduled with President Joe Biden before he dropped out of the race — and would only debate Harris at a Sept 4. debate hosted by Fox News. Trump, however, reversed course several days later and said at a news conference that he would debate Harris on ABC. Trump also proposed debates on Fox News and NBC.

The Harris campaign did not immediately respond to a request for comment about Trump’s social media post Sunday night. Earlier this month, Michael Tyler, communications director for the campaign of Harris and her running mate, Minnesota Gov. Tim Walz, put out a statement that said “the debate about debates is over.”

“Assuming Donald Trump actually shows up on September 10 to debate Vice President Harris, then Governor Walz will see JD Vance on October 1 and the American people will have another opportunity to see the vice president and Donald Trump on the debate stage in October,” Tyler said in a statement, referring to Trump’s running mate, Sen. JD Vance of Ohio.

In his social media post Sunday evening, Trump asked whether “Liddle’ George Slopadopolus,” one of his nicknames for ABC News host George Stephanopoulos, would be involved. “Why did Harris turn down Fox, NBC, CBS, and even CNN? Stay tuned!!!”