US President Donald Trump's supporters are accusing Democrats of disrupting the election voting process.
In Pennsylvania - a swing state - final votes may not be known until this weekend.
The state's Supreme Court has extended the deadline of postal ballots by three days to allow thousands of late-arriving ballots to count - a decision Trump said would allow cheating.
"I think it's a very dangerous decision for our country," he said.
"You can't have these things delayed for many days and maybe weeks. You can't do that. The whole world is waiting. This country is waiting."
The state is also waiting for legal action from Trump if he doesn't win there.
"As soon as that election is over, we're going in with our lawyers," Trump said.
Pennsylvania Attorney General Josh Shapiro says it's important all votes will be counted.
"We are prepared with whatever steps need to be taken to ensure that all legal eligible voters have a safe and secure access to the polls and that their votes will be counted," hs said.
Republican activists have gone to extreme lengths to see Trump win. In Democrat-leaning Texas, they tried and failed to have a judge invalidate 127,000 votes that were cast at a drive-through polling station.
And after months of Trump pushing theories about mail voter fraud, a Federal Judge ordered a last-minute sweep of mail processing facilities, for any missed ballots.
But Trump's supporters remain sceptical of the voting system.
The hashtag #StopTheSteal doing the rounds amongst Trump's supporters accuses Democrats of disrupting the voting process.
Republican activists have been tweeting unverified footage of what appears to be a poll watcher in Philadelphia prevented from entering.
But it's not just the polling stations where the battle between both sides remains heated, with America's militias poised to react to any civil unrest post-election.
Right-wing groups have been the biggest threat, but the new black militia known as NFAC is ready to respond if provoked.
America on edge - not just for a final result, but for what it may bring in the days ahead.
