VIEW THE CRIMINAL COMPLAINT AT THE BOTTOM OF THIS ARTICLE.

Arrests were made Thursday in Houston, Sacramento and Milwaukee in an ongoing terrorism investigation, law enforcement sources told CBS News.

"I can confirm that there were two national security related arrests today, one in Houston and one in Sacramento," Department of Justice spokesman Marc Raimondi told CBS News' Paula Reid. "There is no current threat to public safety associated with these arrests."

The Milwaukee division of the FBI confirms that three subjects were arrested in Wisconsin today. Those charges are unrelated to terrorism. The subjects are expected to be in court tomorrow and more information will be released then. The FBI wants everyone to be aware that there is no threat to the public in Wisconsin.

A law enforcement source told CBS News Justice and Homeland Security correspondent Jeff Pegues the Texas suspect is an Iraqi refugee who has been in the U.S. for at least a year. Authorities believe the suspect became radicalized during his time here in the U.S.

Texas Governor Greg Abbott has already weighed in on the case. Late Thursday, Abbott released a statement before federal authorities had concluded their investigation, which is expected to include an arrest in Milwaukee.

"I applaud the FBI for today's arrest of this dangerous subject," Abbott said. "However, this is precisely why I called for a halt to refugees entering the U.S. from countries substantially controlled by terrorists. I once again urge the President to halt the resettlement of these refugees in the United States until there is an effective vetting process that will ensure refugees do not compromise the safety of Americans and Texans."

CBS affiliate KOVR in Sacramento reported the suspects had been in contact with ISIS.

UPDATE: CBS 58 has obtained a statement from the US Attorney's Office/Eastern District of California about the arrests:

SACRAMENTO, Calif. — A Sacramento resident was arrested today on a federal charge of making a false statement involving international terrorism. Aws Mohammed Younis Al-Jayab, 23, is charged in a criminal complaint that was unsealed today in the U.S. District Court for the Eastern District of California following his arrest. He is in custody and will be making an initial appearance Friday in federal court in Sacramento at 2:00 PM.

The arrest was announced by Assistant Attorney General for National Security John P. Carlin, United States Attorney Benjamin B. Wagner of the Eastern District of California, and Special Agent in Charge Monica M. Miller of the FBI’s Sacramento Division.

“Aws Mohammed Younis Al-Jayab allegedly traveled overseas to fight alongside terrorist organizations and lied to U.S. authorities about his activities,” said Assistant Attorney General Carlin. “The National Security Division’s highest priority is protecting the nation from terrorism, and we will continue to hold accountable those who seek to join or aid the cause of terrorism, whether at home or abroad.”

“According to the allegations in the complaint, the defendant traveled to Syria to take up arms with terrorist organizations and concealed that conduct from immigration authorities,” said U.S. Attorney Wagner. “While he represented a potential safety threat, there is no indication that he planned any acts of terrorism in this country. I commend the FBI’s Joint Terrorism Task Force for their dedicated work on this matter.”

“In today’s complex terrorism environment, our Joint Terrorism Task Force plays an important role in combating the threat of terrorism. The collaboration is stronger than ever and essential to protect our communities from harm,” said Special Agent in Charge Monica M. Miller of the Federal Bureau of Investigation Sacramento Field Office. “The public plays an equal, if not more important, role in protecting the community. We encourage those who encounter individuals who express an intent to do harm or claim allegiance to a terrorist group—whether in person or online—to voice their concerns to law enforcement.”

According to the complaint, Al-Jayab is a Palestinian born in Iraq, who emigrated from Syria to the United States as a refugee in October 2012. Between October 2012 and November 2013, while living in Arizona and Wisconsin, he communicated over social media with numerous other individuals about his intent to return to Syria to fight for terrorist organizations. In those communications, according to the complaint, Al-Jayab discussed his previous experience with firearms and with fighting against the regime in Syria. On Nov. 9, 2013, he flew from Chicago to Turkey, and then traveled to Syria. Between November 2013 and January 2014, Al-Jayab allegedly reported on social media that he was in Syria fighting with various terrorist organizations, including Ansar al-Islam, a designated foreign terrorist organization since 2004. He returned to the United States on Jan. 23, 2014, and settled in Sacramento.

The complaint alleges that on October 6, 2014, Al-Jayab was interviewed by U.S. Citizenship and Immigration Services and responded in the negative to numerous questions, including whether he had ever been a member of any rebel group or militia; whether he had ever provided material support for any person or group engaged in terrorist activity; and whether he had ever been a member of a group, or assisted in a group, which used or threatened the use of weapons against others. Al-Jayab also allegedly stated during the interview that he had traveled to Turkey in late 2013 and early 2014 to visit his grandmother. The complaint alleges that all of those answers were materially false.

If convicted, Al-Jayab faces a maximum statutory penalty of eight years in prison and a $250,000 fine. Any sentence, however, would be determined at the discretion of the court after consideration of any applicable statutory factors and the Federal Sentencing Guidelines, which take into account a number of variables.

The charges are only allegations; the defendant is presumed innocent until and unless proven guilty beyond a reasonable doubt.

This case is the product of an investigation by the Federal Bureau of Investigation and the Sacramento Joint Terrorism Task Force (JTTF), a team of federal, state, and local law enforcement agents and officers investigating domestic and international terrorism. Assistant United States Attorney Jill Thomas and Trial Attorney Andrew Sigler of the National Security Division’s Counterterrorism Section are prosecuting the case. The investigation is ongoing.