Rep. Anthony Weiner (D-N.Y.) won't be effective in Congress if he decides not to resign, Rep. Pete King (R-N.Y.) said.

"He is not going to be effective in Congress. I don’t see how he can represent his constituents," King said Thursday on Fox Business Network's "Imus in the Morning." "What he does in the next few days is up to him, but it has spiraled so fast, I don’t see how he stays on, but right now, I leave that decision to him."

King's comments come as Weiner faces mounting pressure from Democrats to resign his House seat since he admitted on Monday that he had had "inappropriate" correspondence with "about six" women over the past three years, including sending a picture of his waist area clad only in underwear to a woman in Seattle. Weiner initially denied sending the tweet but on Monday admitted it was him.

Since then Weiner has faced mounting pressure to resign from Republicans and, increasingly, Democrats as well.

House Minority Leader Nancy Pelosi (D-Calif.) and Democratic Congressional Campaign Committee Chairman Steve Israel (N.Y.) both have called for the House Ethics Committee to investigate Weiner to determine whether he violated House rules.

In the press conference on Monday, Weiner said he had no plans to resign his House seat.

News broke Wednesday that Weiner's wife, Huma Abedin, is pregnant.