WASHINGTON — US lawmakers on Wednesday called on Secretary of State Hillary Clinton to raise human rights with Vietnam on an upcoming visit, amid fresh convictions of activists and villagers.

The latest appeal was led in part by Representative Loretta Sanchez, a Democrat from California who is facing a tough re-election bid next week against Vietnamese American candidate Van Tran.

Sanchez and three other members of Congress asked Clinton to "raise specific cases and demand actual progress" when she meets Vietnamese leaders at an Asia summit later this week.

"We encourage you to take the opportunity to make human rights a cornerstone of US-Vietnam policy and to demonstrate America's support for the basic freedoms of the Vietnamese people," they wrote.

In a similar letter, Senator Barbara Boxer of California asked Clinton to "urge the Vietnamese government to immediately release all prisoners detained for peaceful advocacy of their beliefs."

The two letters asked Clinton to raise the case of writer and dissident Tran Khai Thanh Thuy. She was sentenced in February to three and a half years in prison on a charge of assault, which she denies.

The letters also criticized Vietnam's recent arrests of members of US-based Viet Tan, which the lawmakers called a "pro-democracy group" but Vietnam bans as a "terrorist organization."

The lawmakers sent the letters just as Vietnam, in two separate cases, convicted three labor activists and six Catholic villagers.

US lawmakers made an earlier appeal for the six villagers in Con Dau, alleging they were tortured as part of Vietnam's clampdown on freedom of worship. Vietnamese authorities deny any injuries, calling the incident a land dispute not connected with religion.