NEW YORK • A man who supplied the weapons that were used by a couple to kill 14 people in San Bernardino, California, in 2015 has been sentenced to 20 years in federal prison.

Enrique Marquez Jr, 28, pleaded guilty in 2017 to providing the two assault rifles used by his friend Syed Rizwan Farook and Farook's wife Tashfeen Malik, in the attack at a holiday party on Dec 2, 2015, with Farook's co-workers at a social services centre.

Marquez also pleaded guilty to plotting two unrealised terrorist attacks in California in 2011 and 2012.

In pleading guilty, Marquez had acknowledged making false statements in connection with his role as a "straw buyer" of the rifles, federal prosecutors said.

Farook and Malik were killed in a shootout with the authorities hours after the massacre, which was the worst terrorist attack on American soil since Sept 11, 2001. Marquez, of Riverside, California, did not participate in the shooting, which also injured more than 20 people.

The authorities have called the shooting an attack inspired by the Islamic State in Iraq and Syria (ISIS) militants, and have pointed out that Malik pledged allegiance to ISIS on Facebook on the day of the shooting.

Federal prosecutors said Marquez had admitted in a plea agreement and in open court that he had also plotted with Farook in 2011 and 2012 to attack Riverside City College and a California freeway.

Those attacks were never carried out, but Marquez had discussed with Farook about using radio-controlled improvised explosive devices for the attacks and bought Christmas tree light bulbs and a container of smokeless powder to use in the devices, federal prosecutors said.

In court last Friday, relatives of the victims asked Judge Jesus Bernal of the US District Court in Central California to impose a lengthy sentence.

"He's a terrorist, your honour," said Mr Gregory Clayborn, whose daughter Sierra was killed. "And if you let him out, he's going to do it again."

NYTIMES