US authorities said two people with ties to the Takfiri group, ISIL, are due in court Friday in California and Texas, including a refugee from Syria accused of returning there to fight alongside ISIL.

US authorities said two people with ties to the Takfiri group, ISIL (so-called Islamic State in Iraq and Levant), are due in court Friday in California and Texas, including a refugee from Syria accused of returning there to fight alongside ISIL.

The arrests come amid heightened security in the United States following last month's assault by a radicalized Muslim couple in California that left 14 people dead and the November terror attacks in Paris.

The attacks added to pressure for more scrutiny of refugees from war-ravaged Syria.

Aws Mohammed Younis al-Jayab, an Iraqi-born Palestinian arrested Thursday who came to the United States from Syria as a refugee in 2012, traveled to Syria the following year where he fought for various terror groups, according to a criminal complaint.

One of those groups was Al-Qaeda affiliate Ansar al-Islam (Partisans of Islam), which previously operated under its own banner in Iraq and Syria.

Listed as a terrorist organization by the United Nations and the US, its Iraqi faction has since merged with ISIL group, though some of its Syrian militants rejected the Takfiri group.

US Attorney Benjamin Wagner was careful to stress that "while (Jayab) represented a potential safety threat, there is no indication that he planned any acts of terrorism in this country."

Another Iraqi-born Palestinian, Omar Faraj Saeed Al Hardan, was indicted Wednesday in Texas for providing material support to the ISIL group. He is due to make an initial court appearance on Friday.

Hardan, 24, was charged with one count each of attempting to provide material support to ISIL procurement of citizenship or naturalization unlawfully and making false statements.

Texas Governor Greg Abbott and other local officials said Hardan's arrest backed their calls for a refugee ban.

"This is precisely why I called for a halt to refugees entering the US from countries substantially controlled by terrorists," he said.

The state's Attorney General Ken Paxton called the arrest a "troubling revelation," using the occasion to take a swipe at President Barack Obama.

"The arrest in Houston of an Iraqi refugee for suspicion of terrorist activities is a troubling revelation -- especially in light of the president's insistence on placing further refugees in Texas," he said.

"My office will continue to press for the right of Texans to ensure that terrorists are not being placed in our communities."