A United States congressman says a Somalia-based terror group is recruiting more Muslim Americans than al-Qaida.

Republican Peter King, the chairman of the Homeland Security Committee in the House of Representatives, told fellow lawmakers Wednesday that the Somali group al-Shabab has successfully recruited 40 Muslim Americans to join its ranks.

King said al-Shabab’s recruitment campaign is increasing the chances the group will strike outside of the Horn of Africa, and said the Muslim-American members “pose a direct threat to the U.S.”

King also said al-Shabab had recruited 20 Muslims from Canada. He said his committee has learned at least 15 Americans and three Canadians have died fighting in Somalia with al-Shabab.

King has been leading a series of controversial hearings on the radicalization of Muslim Americans. Critics say the hearings unfairly target Muslims and result in guilt by association for the Muslim community in America.

King’s critics say Congress should investigate a broad spectrum of domestic terrorist threats, including anti-government hate groups and white supremacists.

King dismissed the protests and criticism as “mindless hysteria” during the committee’s first hearing on the subject in March.