Vietnamese police detained and assaulted family members of a jailed democracy activist and Christian pastor before and during U.S. Ambassador Daniel Kritenbrink�s recent visit to their district in Thanh Hoa province, the political prisoner�s wife said Wednesday.

The house arrest and beating appears to be part of an intensifying crackdown on human rights activists and dissidents six months before the Communist Party of Vietnam�s next five-yearly party congress.

Ahead of the ambassador�s visit, local police visited the Quang Xuong district home of Pastor Nguyen Trung Ton, who is currently serving a 12-year prison sentence for his involvement with the Brotherhood for Democracy dissident group.

�On June 26, officers from the Quang Yen commune police department came to my house, ordering all the family members not to go out of the home for the next few days,� Nguyen�s wife Nguyen Thi Lanh told RFA�s Vietnamese Service.

They locked the gate surrounding the house Monday night, as Kritenbrink was arriving in Quang Xuong the next day.

According to a report by Thanh Hoa Radio and Television, the ambassador was leading U.S. delegation to the northern coastal province to attend an opening ceremony for a local project supported by the embassy�s Fund for Cultural Preservation.

Nguyen Thi Lanh said that on Tuesday morning, she used pliers to break the locks so she could sell goods in the market. Police arrested her there and took her to the Quang Yen police station.

At 4:00 p.m. that day her son Nguyen Trung Trong Nghia left the home to meet his mother at the station.

She said that when her son was on his way there he was attacked by two people, believed to be plainclothes police officers.

�My son was ambushed. They blindfolded and bludgeoned my son�s head with an electric baton, causing him injury,� said Nguyen Thi Lanh.

�A police officer took my son to a health clinic for treatment then brought him back to the Quang Yen police office for booking,� she said.

�This morning, my son returned to the health clinic for more treatment. His face was swollen, and he has broken teeth,� she added.

An official at the Quang Yen police station told the family that the reason for the house arrest was because Ambassador Kritenbrink was visiting their district. The ambassador left Quang Xuong at 5:00 p.m. Tuesday, after which the police left their position at the family�s house.

RFA attempted to contact the Quang Xuong district police office for comment, but nobody answered the phone.

Pastor Nguyen Trung Ton was arrested in July 2017 on charges of �attempting to overthrow the people�s government� and was sentenced to 12 years in prison and three years of probation in April 2018.

Vietnamese authorities have in the past taken interest in the family of political prisoners with Christian affiliations meeting with U.S. diplomats.

In 2016, local police subjected Tran Thi Hong, wife of imprisoned Mennonite pastor Nguyen Cong Chinh to an intense interrogation two months after she met with U.S. diplomats to discuss religious freedom.

Estimates of the number of prisoners of conscience now held in Vietnam�s jails vary widely. New York-based Human Rights Watch said that authorities held 138 political prisoners as of October 2019, while Defend the Defenders has suggested that at least 240 are in detention, with 36 convicted last year alone.