Russians holding dual-citizenship in Turkmenistan must choose a single citizenship or passport by Sunday, according to a decree by Turkmen President Saparmurat Niyazov. The deadline is causing growing concern among Russians in Turkmenistan.

Russian officials estimate that about 100,000 Russians hold dual Turkmen citizenship. They say that some ethnic Russians have fled the Central Asian country because of the abrupt change to the 10-year-old dual citizenship law by presidential decree.

Mr. Niyazov issued the decree after signing a protocol on ending dual citizenship for Russians in Turkmenistan with Russian President Vladimir Putin. But Russian officials have since objected to the Niyazov decree, which makes the stripping of citizenship retroactive and allowed residents just two months to make the difficult decision.

Without a Russian passport, many Russians in Turkmenistan fear they will not be able to leave the former Soviet Republic for visits home, or that they could be stripped of basic rights such as property ownership and access to education.

The Turkmen president has said clearly that anyone who wants to retain dual citizenship should not be allowed to remain in Turkmenistan.

President Niyazov also took additional steps this week that only added to Russian concerns, especially in ordering the creation of a special commission to investigate each and every case of Russian citizenship granted to citizens of Turkmenistan.

Speaking on national television, Mr. Niyazov also said a number of amendments aimed at enhancing security would be introduced to the Turkmen Constitution.

He declined to provide specifics. But Russia's Interfax news agency reports that the proposed amendments would ban Turkmen citizens from obtaining other citizenships, as well as granting security services broader powers to conduct document checks and examine foreigners.

"I cannot imagine the next development in this direction, because nowadays Turkmenistan is even much more totalitarian than it was under [the former] Soviet Union," said Alexei Malashenko, a Central Asia expert with the Moscow Carnegie Center, who views the announced measures with alarm. "I think that practically they do not need more, let us say, protections to resolve some questions with security. But at the same time, after [an attempted] coup d'etat last November, Turkmenbashi is afraid that somebody else may pretend [presume] to occupy his position."

President Niyazov, who prefers to be called Turkmenbashi, the father of all Turkmens, has increasingly cast dual citizens as a threat since an alleged attempt on his life last November in which, he said, several dual citizens were involved. Mr. Niyazov declared himself president for life in 1999.