HANOI, March 17 (Reuters) - Police in Vietnam on Friday arrested a Facebook user who authorities accuse of "attempting to overthrow the state" by sharing content that defamed leaders of the ruling Communist Party, its security ministry said.

Phan Thi Thanh Nha, 39, was accused of posting and sharing 25 articles and videos since 2018 seeking to "distort and defame leaders of the Communist Party of Vietnam and the state," the police-run Ministry of Public Security said in a statement.

Despite sweeping economic reform and increasing openness to social change, Vietnam's ruling Communist Party retains tight media censorship and tolerates little criticism, with dozens of people jailed for speaking out against authorities.

Reuters was unable to immediately identify and contact Nha's lawyer to seek comment.

Nha was also accused by police of joining and recruiting members for the U.S.-based "Provisional National Government of Vietnam", a group listed by the Vietnam as a "terrorist organisation", though not by the United States.

The organisation, which could not be reached by Reuters, has previously pledged loyalty to the now defunct state of South Vietnam. Several people have been jailed in Vietnam accused of recruiting for the California-based group.