WASHINGTON, Nov. 5 (Xinhua) -- U.S. President and Republican presidential nominee Donald Trump said on Thursday he expects "a lot of litigation" over the 2020 election.

Litigation may end up at the Supreme Court, Trump said at the White House briefing room. While making the remarks, he continued to cast doubt over mail-in ballots and vote counting in some states.

U.S. media outlets haven't declared a winner for the presidential election as races in several battleground states, including Pennsylvania, Georgia, and Arizona, are neck and neck and remain too close to call.

Speaking from Wilmington, Delaware on Thursday afternoon, Biden said he continues to "feel very good about where things stand."

"Each ballot must be counted," the Democratic nominee said.