A man who plotted to attack a military complex in the U.S. with machine guns and grenades was sentenced Monday to 18 years in prison.

Abu Khalid Abdul-Latif, 35, also was ordered to be supervised for 10 years after his release.

Abdul-Latif, also known as Joseph Anthony Davis, pleaded guilty in December to conspiracy to murder U.S. officers and conspiracy to use weapons of mass destruction.

Prosecutors argued for a 19-year prison sentence with lifetime supervision following his release, saying Abdul-Latif directed major aspects of the planned attack, including picking the Military Entrance Processing Station in Seattle as a target.

"This was a real attack plot," said Assistant U.S. Attorney Todd Greenberg.

In conversations the FBI recorded with the help of the informant, Abdul-Latif and his co-defendant, Walli Mujahidh, discussed how they wanted to gun down people in the station as revenge for atrocities by U.S. soldiers in Afghanistan, prosecutors said. The military complex is where each branch of the military screens and processes enlistees.

Greenberg countered assertions by the defense that Abdul-Latif was a passive contributor to the plot, noting the defendant had been eager to take possession of machine guns and didn't back out of the plan when he had chances to do so.

Abdul-Latif declined to make a statement in court.

His public defender, Jennifer Wellman, told the judge that her client was remorseful. She argued for 17 years with five years of supervised release, saying Abdul-Latif was manipulated by a confidential informant.

The judge said he found evidence that Abdul-Latif conducted surveillance of the military complex, ordered and purchased weapons and that the location of the target was the defendant's idea.

Abdul-Latif was arrested on June 22, 2011, along with an acquaintance from Los Angeles, when authorities said they arrived at a Seattle warehouse garage to pick up machine guns and grenades to use in the attack.

Investigators had set up the buy after a confidential informant alerted authorities about the plan.

Mujahidh pleaded guilty in the case in December 2011.

Defense lawyers previously filed motions seeking to get some of the prosecution's evidence thrown out, saying the government should not have been able to obtain a secret warrant because there was no indication that Abdul-Latif was involved in international terrorism.

That motion was denied by a federal judge, who said investigators followed proper procedures.