A refugee from Iraq was sentenced by a Houston court Monday to 16 years in prison for seeking to join Islamic State and learn bomb-making skills.

Omar Faraj Saeed al-Hardan, a 25-year-old of Palestinian origin who was born in Iraq and lived in refugee camps in Iraq and Jordan, was accepted into the United States in 2009.

He earned his permanent residency two years later and, according to US law enforcement, in 2013 began communicating with another refugee in California, discussing traveling to Syria to fight for the Al-Nusrah jihadist group.

The next year, he discussed with an FBI informant his hopes of traveling to fight with the Islamic State group and a desire to be trained in making detonators for improvised explosive devices.

He and the FBI informant also practiced shooting with an AK-47, and Hardan posted statements in support of Islamic State online, according to the Justice Department.

He was arrested in January 2016 and charged with providing material support to IS.

"Any person who provides material support to a foreign terrorist organization will be investigated and prosecuted to the fullest extent of the law," said Acting US Attorney Abe Martinez.

President Donald Trump has slashed by more than half the country's annual intake of refugees and placed restrictions on other immigrants, saying it is a conduit for potential terrorists to enter the United States.

Separately, a former Washington-area transit police officer who converted to Islam was convicted of trying to help Islamic State.

Nicholas Young, 37, had tried to help another man join up with IS, only to find that the other man was an undercover FBI informant.

Oddly, Young was also called a neo-Nazi by prosecutors, while his lawyers defended him as simply someone with quirky hobbies.

He faces up to 60 years in prison.