Some 20 women in Islamic hijab worried by rising anti-Muslim rhetoric in the United States watched on a recent night as their self-defense instructor showed them how to punch a would-be attacker.

"Kiai!" shouted Rana Abdelhamid, an Egyptian-American with a black belt in shotokan karate, as she demonstrated the blow.

"I'm fighting - Kiai! That's how loud I want you to be," Abdelhamid, a Muslim human rights activist and native of Queens, New York, told the group.

The women followed her lead, some shouting the martial arts cry louder than others.

The workshops launched by Abdelhamid for women are among a number of similar classes around the United States that have sprung up as Muslims perceive themselves to be under increasing threat.

The feeling has intensified with Republican presidential candidate Donald Trump's call in December to ban Muslims from entering the country.

"You can be attacked at any point. You can be pushed off ... of a subway ledge," said Abdelhamid. She added that headscarves and the hijab can sometimes turn Muslim women into targets.

One of the women in the class, Kristin Garrity Sekerci, an American convert to Islam, said she wanted to be able to defend herself if she were attacked.

"You stand out. It's not fair, but it's the reality. And you have to equip yourself to be able to face that," said Garrity Sekerci, who works with the Islamophobia-tracking Bridge Initiative at Washington's Georgetown University.

Muslim advocacy groups like the Council on American-Islamic Relations (CAIR) say anti-Muslim bias crimes in the United States have tripled since attacks by Islamic militants in Paris in November and shootings by Muslim extremists in San Bernardino, California, in December.

About 80 per cent of the victims in such incidents are women, CAIR officials say.

"There really is a need for Muslim women to protect themselves in this society," said CAIR spokesman Ibrahim Hooper.

The Bridge Initiative says Muslims in the United States are five times more likely to be the victim of a hate crime than they were before the Sept. 11, 2001, attacks.

The women in Abdelhamid's class included a young Palestinian who works at the Pentagon and a middle-aged Yemeni who is learning English.

"You just feel this rush of adrenaline in your body and you just want to conquer the world," Hind Essayegh, a native of Afghanistan, said after the class. "It's really empowering."