The United States is criticizing Vietnam for jailing three activists for up to three years ostensibly for obstructing traffic.
The dissidents were arrested earlier this year while riding in a convoy of motorcycles to visit a former political prisoner.
A court in the southern province of Dong Thap on Tuesday found them guilty of "causing a public disorder."
Bui Thi Minh Hang, the most prominent of the three, received three years in jail. Nguyen Thi Thuy Quynh was jailed for two years, while Nguyen Van Minh got a two-and-a-half year sentence.
The U.S. Embassy in Hanoi says it is "deeply concerned" about the ruling and is alarmed Vietnam is using public disorder laws to silence government critics.
The statement called on Vietnam to immediately and unconditionally release the three activists, along with all other prisoners of conscience.
Human Rights Watch also slammed the conviction, saying Vietnam is resorting to "bogus traffic offences to criminally prosecute activists."
Over the past year, Vietnam has released several dissidents, including some high-profile government critics. It has also slowed the pace of its conviction of activists.
Washington has been trying to develop closer diplomatic and military ties with Hanoi, which is involved in a tense territorial dispute with China, but the U.S. has repeatedly criticized the communist-led government for restricting freedom of expression and religion.