WASHINGTON  - A Pentagon employee was sentenced Friday to 57 months in jail for handing secret military documents over to a Chinese government spy, including classified information on US arms sales to Taiwan. Gregg William Bergersen, 51, pleaded guilty in March of conspiring to hand national defense information over to non-cleared personnel and had faced a maximum sentence of 10 years. On his release Bergersen will have an additional three years of supervised probation. Judge Leonie Brinkema stated the sentence "was sufficient as a deterrent", according to Bergersen's lawyer Mark Cummings. The Chinese agent, Taiwan-born Tai Shen Kuo, is due to be sentenced on August 8, Cummings told AFP. He faces life in prison for spying, the FBI said in a statement. Bergersen was a security and defense weapons systems analyst for the Defense Security Cooperation Agency, which implements the Pentagon's foreign military sales program, and regularly handled classified information regarding US arms sales abroad, including to Taiwan. "During the course of the conspiracy, Kuo cultivated a friendship with Bergersen bestowing on him gifts, cash payments, dinners and money for gambling during trips in Las Vegas," the Justice Department said in a statement. "Unbeknownst to Bergersen, Kuo passed along to an official of the government of the People's Republic of China the information Bergersen had provided to him," the statement said. The Department of Justice has said the US official knew the documents, many of which were about US weapons sales to Taiwan, were classified and should not be shared with outsiders. "Espionage is one of the most serious crimes any American, much less a government official entrusted to serve and protect our nation's defense, can commit," said FBI executive assistant director Arthur Cummings. "The FBI is working diligently with our partners in the law enforcement and intelligence community to safeguard America's national defense information and to ensure individuals who commit such treasonous acts against the United States will be held fully accountable." In May, Kou pleaded guilty to conspiring to divulge national defense information to a foreign government, namely that of China. Also in May, Yu Xin Kang pleaded guilty of aiding an unnamed agent of a foreign government by acting as an intermediary between Kou and the other Chinese agent. She is due to be sentenced on August 1 and could face up to 10 years in prison. In a separate case, Chinese-American engineer Chi Mak was found guilty of spying in May 2007 and sentenced last month to 24 years behind bars. He worked for a US Navy contractor that develops the technology to silence submarines and was described during his trial as a Chinese "sleeper" agent.