Wheaton College has suspended a long-serving professor who decided to wear a hijab for Advent in support of her Muslim neighbours.

Larycia Alaine Hawkins announced in a Facebook post she would don the hijab as an act of devotion because Muslims and Christians "worship the same God".

Wheaton, a prominent evangelical college near Chicago, said the decision to place Hawkins on administrative leave was not for wearing the Islamic head covering but over "significant questions regarding the theological implications of statements that [Hawkins] made about the relationship of Christianity to Islam".

"The College has no stated position on the wearing of headscarves as a gesture of care and concern for those in Muslim or other religious communities that may face discrimination or persecution," said Wheaton president Philip Ryken.

"We support the protection of all Americans including the right to the free exercise of religion, as guaranteed by the Constitution of the United States."

The college responded to a student letter earler this month saying the differences between Islam and Christianity were "fundamental" but invited students to "stand in solidarity with our Muslim brothers and sisters who share our human dignity".

"While Islam and Christianity are both monotheistic," the college's response read, "we believe there are fundamental differences between the two faiths, including what they teach about God's revelation to humanity, the nature of God, the path to salvation, and the life of prayer."

Hawkins is an associate professor who has taught at Wheaton since 2007. She announced last week that she would wear the traditional headscarf as a sign of human, theological, and embodied solidarity.

"I stand in religious solidarity with Muslims because they, like me, a Christian, are people of the book," she wrote in a Facebook post on December 10. "And as Pope Francis stated last week, we worship the same God."

After sustained criticism from a number of evangelical Hawkins posted another social media update pointer to a 2011 Huffington Post article to bolster her claims.

"A holy kiss to you who disavow the idea that Muslims & Christians worship the same God: I love you," Hawkins wrote in a Facebook response to critics. "Peace & respect."