Vietnamese authorities seeking to stop a well-known democracy activist from meeting an American diplomat last weekend deployed an unusual weapon — a group of elderly ladies.

The women blocked the road, preventing a U.S. Embassy vehicle from reaching the house. The vehicle was supposed to take the dissident to a downtown hotel to meet with Deputy Assistant Secretary of State Dan Baer, who was trying to get firsthand accounts from activists and the families of those imprisoned inside the one-party, authoritarian country.

Another activist on the guest list was hauled into a police station until the visiting American had departed.

The efforts made by Vietnamese authorities to stop them show the gulf between the two countries on human rights, and continue to be a stumbling block in forging stronger ties between Washington and a country seen as possible counterbalance against China’s influence in Asia.

Baer was in Vietnam as part of a long-running “human rights dialogue” between the two governments that formalizes America’s efforts to get Vietnam to relax controls on political and religious expression and to stop arresting those pushing for multiparty democracy. Baer had sought meetings with dissidents on Saturday after talks between the two sides on American concerns ended Friday.

“Obviously this taints the whole experience” and raises doubts about the Vietnamese government’s promise to make progress on human rights, Baer said from Oslo, where he stopped on his return from Hanoi.

“What could have been a platform for solid movement has now been marred by behavior that calls into question the sincerity of any commitments they might make,” he said.

As it puts increasing emphasis on Asia in its foreign policy, the United States wants stronger diplomatic, economic and security ties with Vietnam. But the U.S has also made it clear that progress in Vietnam’s human rights record is needed for this engagement to happen quickly and fully. So far, the Communist Party shows few signs of bending. While some members are thought to be open to discussions about gradual change, its leaders are not listening, anxious about losing power and access to lucrative sections of the economy.

This year’s human rights dialogue was delayed by several months because of American concerns that the previous session in Washington in November 2011 had failed to bring any substantive changes. According to Human Rights Watch, in 2012 at least 40 dissidents were convicted and sentenced to prison; 40 more were locked up in the first six weeks of 2013.

Baer wanted to meet Nguyen Van Dai and Pham Hong Son, two dissidents well known to Western governments and rights organizations. They have each served four-year prison terms in the past. Both are under frequent surveillance and are often harassed, yet remain publicly committed to challenging the party, prepared to accept the risks to them and their family in doing so.

Dai said he informed the political officer at the American Embassy that police and other security officers were gathering at his home, preventing him from leaving for the meeting. The officer told him he would drive to the house to pick him up. But when the car arrived, it was blocked by about 10 women from the neighborhood who had been told by authorities to stand on the road, Dai said.

“I don’t know why they used this crazy way,” Dai said. “I think it is the first time.”

Asked for comment, the Vietnamese government responded in a statement: “Vietnamese authorities created the conditions for the delegation led by Daniel Baer to meet with some individuals of concern to the American side.”

Baer said he was able to meet with families of two political prisoners — Le Quoc Quan and Cu Huy Ha Vu — for 1 ½ hours Thursday even though authorities made it difficult for them to get out of their homes to meet him. Quan, a lawyer who studied in the United States, was arrested late last year after he and his family endured months of harassment. Baer also visited a prison to meet Father Ly, a Roman Catholic priest serving an eight-year sentence.

By using members of the public to block the embassy car, the Vietnamese government might have been seeking a way to plausibly deny a role in preventing Baer from meeting Dai.

“If the government hadn’t wanted that road blocked, it could have cleared it up,” said Phil Robertson from Human Rights Watch. “The outcome they wanted is achieved without generating the blowback or sort of criticism that would have come down on the government if there had been a line of police stopping the car.”

Both Dai and Son have met with senior U.S. officials in the past, and Baer appeared surprised the meetings were blocked.

“I’m not in the habit of asking permission to meet citizens,” Baer said. “We certainly don’t restrict who they can meet with in the US.”

Several Vietnamese journalists attended a news conference given by Baer on Friday evening, but the event was not covered by the local media, which are owned and controlled by the Communist Party. A commentary published in the party’s leading paper, Nhan Dan or “The People,” a few days ahead of Baer’s arrival suggested he was in for a rough ride.

“Does Daniel Baer not see a problem looking at the human rights issue in Vietnam through the eyes of anti-communist Vietnamese American extremists?” it asked, repeating an often cited belief that South Vietnamese who fled the country after the Vietnam War are the source of hostility toward Hanoi in the United States. “One cannot believe a group of people who still feel bitter about the defeat nearly 40 years ago. Daniel Baer and some American politicians should soon change their attitude about this issue.”

The United States has a stated goal of advocating for human rights norms around the world, but a coterie of Congress members that have South Vietnamese diaspora communities in their districts are pressing the administration to give it particular emphasis in Vietnam. The diaspora fled to the U.S. after the defeat of the United States and its South Vietnamese allies by the Communist army of North Vietnam.

Son said he had met Baer in 2010 and 2012 on previous visits to Vietnam, and described him as “very nice and enthusiastic in his concern about human rights.”

The dissident said police officers came to his house Saturday morning and ordered him to come to the local station, ostensibly because a resident had complained about an interview he had given to the BBC’s Vietnamese radio service where he discussed proposed changes to the country’s constitution. He went along with them, but was never interviewed about the alleged complaint.

“I just laughed,” he said. “I have encountered similar incidents many times. Our government, our party to be more precise, has a wide variety of cunning ways of harassing people. The party does not want people like me to meet people from abroad like Dr. Baer.”