(Reuters) -MP Materials ( MP ) posted a smaller-than-expected second-quarter loss Thursday, as the U.S. rare earths miner benefited from higher production amid rising demand.

Its shares jumped over 12% in trading after the bell. The stock has gained nearly 356% so far this year to last close.

The company - which operates the only U.S. rare earths mine in Mountain Pass, California - has been in the spotlight as President Donald Trump's administration ramps up efforts to build out a domestic supply to reduce dependence on China.

Last month, the company signed a multibillion-dollar deal with the U.S. government to boost output of rare earth magnets, which are widely used to build weapons, electric vehicles and many electronics.

The deal, which would make the Pentagon the company's biggest shareholder, was followed by a $500 million deal with Apple for the supply of rare earth magnets to the iPhone maker.

Production for neodymium and praseodymium (NdPr) - the two most in-demand rare earths - increased 119% to 597 metric tons in the second quarter ended June 30.

The Las Vegas-based company posted an adjusted loss of 13 cents per share, compared with analysts' expectations of 19 cents loss per share, according to data compiled by LSEG.

(Reporting by Vallari Srivastava in Bengaluru; Editing by Sriraj Kalluvila)