US lawmakers accused Yahoo of giving false information to Congress and asked that chief executive Jerry Yang appear before a committee to explain the internet search company's role in the imprisonment of a Chinese dissident.

Tom Lantos, the Democratic chairman of the House foreign affairs committee, said a congressional probe had established that Yahoo provided "false information" to Congress during a hearing last year in which the group said it knew nothing about the nature of an investigation into an activist when it gave Chinese authorities information about his e-mail account and contents of his e-mails. Shi Tao, the activist, was arrested and sentenced to 10 years' imprisonment after Yahoo divulged the identifying material.