US President Donald Trump has accused his opponents of electoral malpractices in Tuesday presidential election .
According to the Republican candidate , his opponents are casting votes after polls are closed .
“ We are up big but they are trying to steal the election . We will never let them do it . Votes cannot be cast after the polls are closed !” he tweeted .
With polls gradually closing across the United States Tuesday , a long night of waiting for results ahead .
The first results are trickling in , with US media projecting wins for the Republican incumbent so far in 13 states including Indiana, Kentucky, Oklahoma , Tennessee and West Virginia — all states he won in 2016 .