Dong Tam residents were protesting a move by Viettel, a military-owned telecommunications company, to seize 145 acres of disputed land, the state-controlled news site VnExpress reported Thursday.

The land was once owned by the military and was transferred to Viettel for a defense-related project in 2015, according to an online report by the state-run newspaper Dan Tri. It said villagers had been trespassing on the land. Neither Viettel nor any villagers directly involved in the hostage crisis could be reached for comment on Friday.

Activists in Hanoi said that the dispute began last weekend, when police officers and plainclothes security forces entered Dong Tam, which sits among rice paddies about 25 miles south of Hanoi, to evict the villagers from the land. The villagers resisted and managed to capture 38 of the police officers and security officials in the process, the activists said.

After news of the uprising spread online, some activists visited the village, said Doan Trang, a journalist in Hanoi who does not work for the state-controlled news media. But security was later tightened, and several human rights activists from Hanoi were placed under house arrest, she said.

Experts and activists said the dispute was a vivid reminder of a quandary that Vietnam has wrestled with for decades: how to allocate land in a Communist country that allows quasi-private ownership rights but still considers all land to be state property.

“Things will not stop at Dong Tam,” said Le Dung Vova, a prominent Vietnamese activist and writer. “Similar incidents will keep happening everywhere, with different levels of intensity, especially as land resources become more scarce.”

Land disputes are common on the fringes of Vietnamese urban areas, where land values are often high; villagers are typically compensated at prices well below market rates for agricultural land that is later rezoned for other uses. John Gillespie, a professor at Monash University in Australia who is an expert on land reform in Vietnam, said in an interview that the disputes tended to be more violent when villagers perceived that business interests outweighed public ones.

Videos of confrontations between villagers and the riot police in rural Vietnam are widely shared on YouTube and Facebook, which are not blocked in the country. Some villagers are supported by networks of urban activists as they campaign against the officials or the state-affiliated companies behind the evictions.

The disputes occasionally turn violent, forcing provincial or even national officials to intervene. In 2012, for example, after a farmer shot at police officers who were trying to evict him from his land in the northern port city of Haiphong, the prime minister at the time, Nguyen Tan Dung, stepped in to say that the eviction had been illegal.

In 2013, Vietnam tweaked its land law in ways meant to introduce more transparency into eminent domain cases. A United Nations-financed survey of public administration in Vietnam later found that the percentage of citizens who reported land seizures in Vietnam had declined slightly, to 6.8 percent of respondents in 2016 from over 9 percent in 2013, suggesting that the law may have helped reduce land seizures by local officials.

But experts say land disputes continue, in part, because the 2013 revisions do not allow private ownership or set clear definitions of what qualifies as the public interest in eminent domain cases.

The Dong Tam conflict is not exceptional, said Andrew Wells-Dang, a senior governance adviser at Oxfam Vietnam who has worked on land policy in the country. “It’s simply been large and gotten a lot of attention,” he said.

Embassy officers from some Western countries met with Hanoi officials this week and asked them to refrain from using violence in Dong Tam, said a Western diplomat in Hanoi who spoke on the condition of anonymity, citing official protocol.

On Thursday night, Dong Tam was quiet except for a group of villagers who were keeping a vigil outside the barricades, shining flashlights at passing cars. A central street was decked with national flags for a coming public holiday commemorating the 1975 victory over the United States in the Vietnam War.

There was no visible police presence.

The blogger in Dong Tam said by telephone on Friday that about 20 journalists were waiting there for the top official of Hanoi, Nguyen Duc Chung, to arrive for expected talks with the villagers.

It appeared that violence would be averted for at least another day because of the talks, Ms. Trang said. But the farmers, she said, will almost certainly be punished once the conflict has settled down.

“That’s the police’s tradition,” she said. “Never in history do they concede to the citizens.”