HANOI, Vietnam — Vietnam has released a prominent government critic convicted of spying against the communist government, two weeks before Vietnam’s president makes a historic visit to America, an official said yesterday.

Nguyen Vu Binh, 39, was released from Nam Ha prison on Saturday under a presidential amnesty, said Pham Hong Canh, deputy director of the prison in Ha Nam province, 40 miles south of Hanoi.

Mr. Binh, a former journalist, was one of Vietnam’s first “cyber-dissidents,” who used the Internet to spread pro-democracy views. In late 2003, he was convicted of spying and sentenced to seven years in prison and three years of house arrest. The court said he had committed espionage by gathering anti-government information and documents for overseas “reactionary organizations.”

Mr. Binh’s early release comes as Washington has grown increasingly concerned about the arrest and jailing of a number of dissidents in Vietnam. President Triet is scheduled to make a June 22 visit to America, the first by a Vietnamese president. After the White House formally invited Mr. Triet to Washington, Vietnam’s Vice Foreign Minister Le Van Bang announced last week that Hanoi would release three dissidents before the two presidents meet.

Mr. Binh was arrested in September 2002 for writing an article that circulated on the Internet criticizing a border agreement between Vietnam and China. A month earlier, he joined 20 others in signing a petition to government leaders demanding legal reforms to protect human rights and establish an independent anti-corruption body.