MOSCOW, May 15 -- No international military-political bloc should interfere into the Ukrainian crisis, chief of the Moscow-led Collective Security Treaty Organization (CSTO) said Thursday.

"Neither NATO, nor CSTO should attempt to influence the situation in Ukraine in any way today," Nikolai Bordyuzha told the Interfax news agency, adding outside involvement would be counterproductive and only lead to further escalation of tension in that country.

"The Ukrainians themselves must sort out the conflict -- first of all those forces who have been in power and their opponents," he said, "In no case should other countries and alliances interfere."

Pro-independence forces in Donetsk and Lugansk regions in eastern Ukraine established "people's republics" in early April and proclaimed statehood at the referendums on May 11.

Meanwhile, Bordyuzha said the events in Ukraine posed direct threat to CSTO security due to common borders and close ties between people at the grassroots level. Anti-Russian sanctions imposed by the West have also negatively impacted the situation, he added.

The official also accused NATO of inciting general tension by threatening to beef up its military presence near Russian borders.

In April, the CSTO, which comprises Russia, Armenia, Kazakhstan, Kyrgyzstan, Tajikistan and Belarus, suspended cooperation with NATO over the two blocs' confrontation around Ukraine.

Earlier this year, Bordyuzha criticized NATO's "self-propaganda" through the Ukraine crisis, saying that NATO Secretary General Anders Fogh Rasmussen promoted himself through Ukraine's domestic political problems.