Moscow - (AFP) - Russian President Vladimir Putin acknowledged on Tuesday that the situation is "very difficult" in the four regions of southern and eastern Ukraine that Moscow declared annexing without fully controlling them.

"The situation in the Donetsk and Luhansk People's Republics, as well as in the Kherson and Zaporizhia regions, is very difficult," Putin said.

Putin was speaking in a video addressed to employees of the Foreign Security and Intelligence Service and the protection of senior officials, who annually celebrate their "professional holiday" in Russia on December 20.

Putin praised the performance of the Russian security services who work in the "new regions of Russia," stressing that "the people who live there are Russian citizens" who depend on the "protection" of these services.

The Russian president, who formerly worked in the KGB, called for "extreme concentration" by counterintelligence services.

"It is necessary to severely suppress the work of foreign intelligence services and effectively identify traitors, spies and saboteurs," he said.

In September, the Russian president announced the annexation of four Ukrainian regions (Donetsk, Luhansk, Zaporizhia and Kherson regions) that are partly controlled by the Russian army, after holding local "referendums" that were denounced by Kiev and the West.

But in November, Ukraine recaptured Kherson, the capital of the region of the same name, which was a major setback for Moscow after a several-week counteroffensive.