The standoff began over the weekend in the suburban district of My Duc when police clashed with villagers who allege their land was illegally seized for sale by a military-run telecoms firm.
Some villagers were arrested.
Online newspaper Vnexpress reported that more than 30 people, many of them riot police, have been held by villagers.
Lawyer Tran Vu Hai told The Associated Press that Hanoi Mayor Nguyen Duc Chung in a phone call Monday morning assured village representatives that the remaining six villagers had been released. He also pledged direct talks to address their grievances on Tuesday.