Rep. Peter King (R-N.Y.) warned Thursday that Sunni militants in Iraq could build a dirty bomb with uranium seized during their march on Baghdad.

“We should be very concerned,” King said on Fox News’s “The Kelly File.” “And the fact that the government or the administration is trying to pass this off as not being enriched and perhaps not being weapons grade, the fact is it still could be used for a dirty bomb.”

{mosads}Iraqi Ambassador to the United Nations Mohamed Ali Alhakim informed U.N. officials last month that militants from the Islamic State in Iraq and Syria (ISIS), a Sunni insurgent group, had gained control of a former chemical weapons plant and seized 90 pounds of uranium compounds from the University of Mosul.

State Department spokeswoman Jen Psaki told reporters Thursday that the International Atomic Energy Agency (IAEA) was downplaying any concern over the uranium.

“I would point you to the comments and the statement made by the IAEA today, that they believe the material involved to be low-grade and not presenting a significant safety, security, or nuclear proliferation risk,” she said.

“Of course, they’re the appropriate identity to make any decision about whether there is a risk or concern, but it doesn’t seem that is the case at this point in time,” Psaki added. 

King, the former chairman of the House Homeland Security Committee, said ISIS could still cause significant damage with the seized material.

“You get uranium, you have radioactive material and you case it in explosives and conventional explosives and the blast would kill many people and the impact of the radiation will contaminate an area,” he said.

King criticized the Obama administration for the security meltdown in Iraq, where ISIS has captured large parts of the country.

“Well, first of all, not to relive the past but this wouldn’t have happened if President Obama hadn’t pulled all of our troops out,” he said.

King said the U.S. should use “air power” to attack ISIS and send in U.S. special forces, not to “pick out targets” but not for combat operations.

Obama has authorized 800 military advisers to be deployed to Iraq to help local security forces against ISIS.