Rep. Steve King (R-Iowa) is calling for comprehensive immigration reform to be put on hold in light of Monday's bombing at the Boston Marathon, citing speculation (since deemed misplaced) that the attacker was a student from Saudi Arabia.

"Some of the speculation that has come out is that yes, it was a foreign national and, speculating here, that it was potentially a person on a student visa,” King told National Review. “If that’s the case, then we need to take a look at the big picture.”

He added that "we need to be ever vigilant," and that security should be the focus right now, not a path to legalization. "If we can’t background-check people that are coming from Saudi Arabia, how do we think we are going to background check the 11 to 20 million people that are here from who knows where?”

King has long been critical of loosening restrictions on immigration. Although he has said he agrees with the "very broad guidelines" laid out by  a group of senators in January, he has repeatedly argued that border security should be a primary concern and that we should be bringing in only the most valuable immigrants. (In one appearance he compared the immigration process to choosing "the pick of the litter" among hunting dogs, a comparison that angered many Hispanic groups).

Rep. Candice Miller (R-Mich.), likewise called for a stronger visa tracking system and noted her opposition to making it easier for travelers from Saudi Arabia to enter the country.

Authorities don’t yet know the motive behind the Boston bombing, which has killed at least three people and injured many more. President Obama said Tuesday that while "any time bombs are used to target innocent civilians, it is an act of terror,” it is unknown whether the attack was the work of a terrorist group or “a malevolent individual.”

A Saudi national injured in the bombing, who had been the subject of intense media speculation, is regarded as a witness, not a suspect, a U.S. law enforcement official told the Post. The Saudi, who is at a Boston hospital, is in his 20s and is in the United States on a Saudi scholarship to study at a university in the Boston area.