Donald TrumpDonald John TrumpTrump opens new line of impeachment attack for Democrats Bloomberg to spend 0M on anti-Trump ads in battleground states New witness claims first-hand account of Trump's push for Ukraine probes MORE on Thursday joked that he'll be taking a "nice long vacation" if his poll numbers don't go up by November.

ADVERTISEMENT

"I just keep doing the same thing I'm doing right now," the GOP presidential nominee said when asked on CNBC how he would close the gap in battleground states where he is trailing Democrat Hillary ClintonHillary Diane Rodham ClintonWhat are Democrats going to do once Donald Trump leaves office? Trump to hold campaign rally in Florida later this month Krystal Ball accuses Democrats of having 'zero moral authority' amid impeachment inquiry MORE.

"And at the end, it's either going to work or I'm going to have a very, very nice long vacation."

Support for Trump has been dropping in polls following last month's Democratic National Convention, and he trails Clinton both nationally and in several battleground states.

Clinton has 48 percent support nationally to Trump's 40.3 percent in the RealClearPolitics average

Trump has created several controversies in recent weeks. He faced bipartisan criticism for his attacks on the family of Humayun Khan, an Army captain killed in Iraq in 2004.

Trump last week declined to endorse Speaker Paul RyanPaul Davis Ryan Retirees should say 'no thanks' to Romney's Social Security plan California Governor Newsom and family dress as 2020 Democrats for Halloween DC's liaison to rock 'n' roll MORE (Wis.) and other top Republican lawmakers before eventually backing them days later.

And earlier this week, he drew criticism after suggesting that gun rights supporters could take action against Clinton, a remark many took as advocating violence.