Khizr Khan has challenged Donald Trump to take a US naturalisation test after the Republican nominee proposed that all immigrants should declare their ideological beliefs before being allowed into the country.
Mr Khan, a Gold Star parent of the slain Muslim solider Humayan Khan, first addressed Mr Trump directly at the Democratic National Convention in July, urging him not to smear Muslims’ characters and to read the US constitution.
His latest attack is a response to Mr Trump’s keynote speech on Monday in Youngstown, Ohio, where the Republican outlined his plan on terrorism and how to combat Isis.
One part of the plan was to make visa applicants undergo an "ideological test" before entering the country, a form of "extreme vetting" to screen out anyone who has a "hostile attitude" to the US.
Mr Khan, who became a US citizen after emigrating from Pakistan in 1980 and now lives with his wife Ghazala in Virigina, condemned the plan.
"I challenge Trump to take the naturalisation test with me any day. His is demagoguery and pandering for vote. A divider like Trump can never be the steward of this country," he told the Huffington Post, referring to the test that immigrants must pass to become a US citizen.
Senate Minority Leader Harry Reid also challenged Mr Trump to take the test, calling him a "spoiled, unpatriotic drain on society" in a statement on Monday.
The Khans' son died in 2004 during his military service in the Iraq War. Humayun Khan was posthumously awarded the Purple Heart and the Bronze Star.
Last week, the co-chairman of the Trump campaign, Carl Paladino, said that the Khans did not need to be referred to as "Gold star parents" because Mr Khan is "a member of the Muslim Brotherhood".
