MOSCOW/BISHKEK (Reuters) - Russia said on Thursday that Kyrgyzstan had descended into chaos and that Moscow was obliged by a security treaty to prevent a total breakdown in the country, where rival groups have claimed power in post-election unrest.

The Central Asian nation, where Russia has an airbase, has been gripped by instability since parliamentary elections on Sunday which government critics and western monitors said were marred by vote-buying.

Protesters stormed government buildings on Tuesday and various groups have said they are in charge.

Parliament failed to gather a quorum in an overnight session to agree on who should take over from ousted ministers, deputies said earlier on Thursday, prolonging a power vacuum.

“The situation looks like a mess and chaos”, Kremlin spokesman Dmitry Peskov told a briefing, referring to Russian obligations under a security treaty between the two countries to avoid a complete breakdown of government.

Peskov also confirmed that Alexander Bortnikov, the head of Russia’s FSB security service, had spoken to the new acting security chief of Kyrgysztan, Omurbek Suvanaliyev, on Wednesday.

Suvanaliyev, formerly deputy head of the security council, took over when government leaders were driven from power.

The committee he now heads on Thursday issued a statement saying Kyrgyz security forces would not be used as a tool by any party and demanding that all political forces negotiate and restore the rule of law.

Suvanaliyev also told Russia’s Interfax news agency that Kyrgyzstan was tightening border controls to ensure security. Border guards later clarified that they had been given a list of people barred from leaving the country.

The unrest in Kyrgysztan is the third outbreak of instability in former Soviet republics this year. Mass protests are ongoing in Belarus and fighting has broken out over the ethnic Armenian enclave of Nagorno-Karabakh in Azerbaijan.

In 2014, Russia annexed Crimea from another ex-Soviet republic, Ukraine, where a conflict between Kiev and Russian-backed separatists in the east is simmering.

In Kyrgyzstan, three opposition groups have each proposed their candidates for interim prime minister, a figure who would need to oversee a repeat vote in the coming months, Kyrgyz news website Akipress quoted deputy Ryskeldi Mombekov as saying.

In addition to Sadyr Zhaparov and Tilek Toktogaziyev, who have already made their ambitions clear, Mombekov said Omurbek Babanov, who has already served as the cabinet head, had emerged as a contender.

But the outgoing parliament has itself split into two groups that were meeting separately outside the main ransacked government building, Mombekov said. The group that met overnight in a hotel only included 40 MPs, whereas major decisions such as naming a cabinet require a 61-vote majority.

Another MP, Elvira Surabaldieva, posted a video from the meeting online, saying it had failed to pass a motion to impeach President Sooronbai Jeenbekov.

Jeenbekov’s whereabouts have remained unknown since Tuesday though his spokeswoman told Akipress he has spoken by phone to new parliament speaker Myktybek Abdyldayev and told him he saw his own mission as restoring the rule of law.

Kyrgyzstan’s central bank allowed financial institutions to reopen on Thursday after their closure on Tuesday, as business associations warned the nation of 6.5 million could face food shortages if banks and tax offices remained shut and public safety could not be guaranteed.

Sunday’s election handed victory to two establishment parties, one of them closely linked to Jeenbekov.

Eleven other parties refused to accept the results and the central election commission annulled them on Tuesday as it became clear Jeenbekov was losing his grip on power.

One person has been killed and more than a thousand have sought medical help since the unrest broke out, as vigilante units formed by Bishkek residents scuffled with protesters and looters.

However, acting interior minister Kursan Asanov, who took over this week after running in the election as an opposition candidate, said police and vigilantes had managed to prevent mass looting in the capital.

He vowed to stop any attempts to further destabilise the country where ethnic violence left hundreds dead after the ouster of president Kurmanbek Bakiyev in 2010 in another revolt.

Asanov also urged parliament to convene and install a legitimate cabinet, describing the current situation as stable but tense.