Senator John McCain and other Republican leaders have condemned Donald Trump’s remarks about the family of a fallen United States Muslim soldier.
Mr McCain said Mr Trump did not have an “unfettered license to defame those who are the best among us”.
BBC said that Mr Trump has come under fire for criticising the Muslim American parents of a US soldier killed in Iraq.
Democratic lawmakers and the soldier’s father have called on Republicans to disavow Mr Trump.
“I cannot emphasize enough how deeply I disagree with Mr. Trump’s statement,” Mr McCain said in a statement.
“I hope Americans understand that the remarks do not represent the views of our Republican Party, its officers, or candidates.”
Mr McCain, a war veteran and the party’s 2008 presidential nominee, thanked the Khan family for immigrating to America, adding “we’re a better country because of you.”
Last year Mr Trump sparked a backlash after he said Mr McCain was not a war hero because he was captured in Vietnam.
The latest escalation comes as Republican leaders have stepped forward to rebuke Mr Trump’s fight against the Gold Star parents.
In the US, parents who have lost a child in war are known as Gold Star families.
The couple’s son, US Army Capt Humayun Khan, was killed by a car bomb in 2004 in Iraq at the age of 27.