Uzbek and Kyrgyz officials have placed armored vehicles and soldiers near a disputed border area as heightened tensions have prompted the Russian-led Collective Security Treaty Organization (CSTO) to meet in Moscow.
The majority of the twisting 1,314-kilometer-long Uzbek-Kyrgyz border is still undefined, and conflicts on and near border crossings are often violent. Several in recent years have ended with people being shot dead.
The current quarrel centers around a small mountain known in Uzbek as Ungar-Tepa and Unkur-Too in Kyrgyz, which lies on the undemarcated Kyrgyz-Uzbek border about 10 kilometers from the western Kyrgyz town of Kerben.
On March 18, two Uzbek armored personnel carriers and some 40 soldiers suddenly appeared at the border crossing near Ungar-Tepa at a place called Chala-Sart in Kyrgyz.
The Uzbek maneuver was considered by Kyrgyz officials to be a violation of bilateral agreements between Bishkek and Tashkent not to "militarize" a tense situation along their common border.
Kyrgyzstan responded by sending dozens of armed border guards to the frontier as well as moving members of its special forces unit, the Scorpions, to the area.
The tense situation and perhaps Uzbekistan's massive military advantage over Kyrgyzstan led Bishkek to call for the CSTO's Permanent Council to hold an "extraordinary session" on the issue.
The CSTO -- which Uzbekistan left in 2012 -- met on March 22 and "expressed concern" with the situation. It also agreed to send its deputy secretary-general, Ara Badalian, to the disputed area to study the situation.
Ethnic and territorial disputes are particularly sensitive in southern Kyrgyzstan, which is home to hundreds of thousands of ethnic Uzbeks.
Kyrgyz and ethnic Uzbeks have had bloody conflicts in Kyrgyzstan in the past, most recently in 2010 when hundreds of people -- mostly Uzbeks -- were killed in bloody riots that also displaced tens of thousands of people.
The latest actions by the Uzbek military along the border were seized upon by Kyrgyz opposition leaders, who have sharply criticized the country's government for its weak response to the moves by Uzbekistan.
At a rally in Kerben on March 22, Voice of the People opposition movement leader Azimbek Beknazarov told an agitated crowd of a few hundred people that Kyrgyz officials "have never been able to talk to foreigners, to the authorities of other countries, as equal partners."
"And because of this we have surrendered Kyrgyz territory to China," he said in a reference to Kyrgyzstan ceding thousands of square kilometers of its Uzengu-Kuush region to Beijing in 1999.
He added that Kyrgyz officials were "now saying that those 12 hectares of land [that make up the Ungar-Tepa mountain] have never been fully delineated [with Uzbekistan]. Well it has been defined as it has been used by Kyrgyz people for ages. Is there anyone here who would say this piece of land is in fact disputed with Uzbekistan?"
With Beknazarov and other opposition leaders pledging to hold rallies in Kyrgyzstan's often restive south ahead of March 27 local elections, Kyrgyz Prime Minister Temir Sariev travelled to the remote site to address the crowd.
"I have always said that the most difficult issue faced by our nation is about our borders in the south.... All the issues raised here today are currently under discussion, and we have been doing everything to resolve the situation," Sariev said.
He pledged to do so through "talks and negotiations" and said that President Almazbek Atambaev was involved in the process.
"There is no need to worsen the situation," he added. "Dear compatriots, please, let us stay away from hot emotions.... We will resolve the issue."
But his message received a lukewarm response from the crowd, which at a "kurultai," or people's congress, held earlier on March 22, made an appeal to Russian President Vladimir Putin to help resolve the issue.
Opposition leader Ravshan Jeenbekov said the call to Putin had "shocked" him.
"What if we give authority [to resolve the issue] to Putin and he will decide in Uzbekistan's favor?" asked Jeenbekov.
As of March 23, most of the armed guards and troops on both sides of the border had been pulled back to secondary positions, RFE/RL's Kyrgyz Service reported, although the armored personnel carriers remained.