Some Republican lawmakers said they will support Trump even though they originally preferred other presidential candidates.

The 69-year-old Trump surged to the top of the Republicans' one-time field of 17 candidates with calls to build an impenetrable wall along the U.S.-Mexican border to halt the stream of illegal immigrants into the United States and to deport the 11 million already in the country.

He has won more than 10 million votes in state-by-state party nominating contests, with his last two challengers dropping out of the race for the party's presidential nomination after Trump scored an impressive win in last week's contest in the Midwestern state of Indiana.

Neither Trump nor Clinton has officially clinched their parties' presidential nominations yet, but they are trading verbal taunts at each other.

Attacking the Clintons

At a rally Saturday, Trump, who is married to his third wife and through the years has bragged about sexual exploits, lampooned Clinton for the marital infidelities of her husband, former U.S. President Bill Clinton.

"She's married to a man who was the worst abuser of women in the history of politics," Trump said.

Clinton has disparaged Trump as unfit to be the country's commander in chief.

"We can't have a loose cannon in the Oval Office" at the White House, she told cheering supporters at a rally.

Numerous polls show Clinton ahead of Trump in the election to pick the successor to President Barack Obama, who leaves office next January.