DUBAI (Reuters) The Islamic State group condemned as an "apostate" a U.S. Muslim soldier killed in Iraq whose story has reignited debate in the 2016 presidential election on the role of Muslims in American life.

Dabiq, the militant group's online magazine, showed a picture of Army Capt. Humayun Khan's tombstone in Arlington National Cemetery with a caption, "Beware of dying as an apostate."

An accompanying article, penned by an unnamed "American convert in the Islamic State," urged Muslims to resist Western influences and to either migrate to Islamic State-controlled lands or carry out lone attacks.

"Reject these calls to disunity and come together. Live the life of Islam, for which you have already left the path of falsehood," the militant wrote.

"You are behind enemy lines, able to strike them where it hurts them most," the article published Sunday (July 31) added.

Khan's death in a bomb attack in Iraq in 2004 re-emerged as an election issue when his father gave a speech at the Democratic National Convention on Thursday in which he paid homage to his son.

Khizr Khan, a U.S. citizen of Pakistani origin and a Muslim, also criticized Republican presidential nominee Donald Trump for proposing a temporary ban on Muslims entering the United States and asked if the candidate had read the U.S. Constitution.

Trump rejected the criticism and questioned whether the soldier's mother was allowed to speak during the couple's appearance at the podium.

Ghazala Khan later said the outspoken billionaire was ignorant of Islam and of sacrifice.

Trump has stoked outrage during his unorthodox campaign by supporting profiling for Muslim Americans in the wake of a deadly shooting by a U.S.-born Muslim man that killed 49 people at a gay nightclub in Orlando in June.

Hillary Clinton, the Democratic nominee, has said the comments and other pointed remarks about American minorities show Trump is unfit to be president.

(Reporting By Noah Browning)