Some 150 people occupied the regional administration building in the town of Jalal-Abad near the Uzbek border for a third day on Saturday, as more than 100 soldiers and police guarded the perimeter of the structure to prevent more protestors from entering inside.
Another 50 protestors camped out on the building's front lawn and around 700 demonstrated in the square outside chanting "Down with Akayev", referring to Kyrgyz President Askar Akayev.
"We're keeping order inside the building - we've been standing here round the clock and we'll carry on," Gamal Soronkulov of the Justice and Progress opposition party said.
Poll falsification protests
The protest is one in a string that have occurred in villages and towns across the south of this former Soviet republic against alleged falsification of the results of 27 February parliamentary elections - due to go to a second round in most districts on 13 March.
As in several other districts protestors in Jalal-Abad are supporting a second-placed ethnic Kyrgyz candidate, Jusupbek Bakiyev, who was defeated by an ethnic Uzbek candidate, Kadyrzhan Batyrov.
On Sunday, protestors from outlying districts of Jalal-Abad region, angered over other election results, began making their way to the regional centre by public transport.
Police set up checkpoints along major routes, while also increasing security around Akayev's office in the capital Bishkek.
"Of course it will be peaceful if they don't provoke anything," said Usen Sydykov, a former ambassador to Moscow turned opposition figure
He did not specify who he thought might challenge the protestors.
Akayev, 60, has held Kyrgyzstan's top post since the end of Soviet rule in 1991 through a series of elections and referenda judged by the West as flawed.
Het has vowed to stand down at presidential polls on 30 October.