BUCHAREST, Romania (AP) — Among the sites of the former Soviet Union's “frozen conflicts,” a long and narrow strip of land in Moldova has been the most stable for three decades. Trans-Dniester hasn't seen fighting since the end of a separatist war in 1992.

But explosions in the past two days have raised concerns that Russia's war in Ukraine could extend there. About 1,500 Russian troops already are stationed in Trans-Dniester. Another outbreak of hostilities would pose a severe challenge to Moldova, one of Europe’s poorest countries.

WHAT IS TRANS-DNIESTER?

Trans-Dniester extends some 400 kilometers (249 miles) between the eastern bank of the Dniester River in Moldova and the country's border with Ukraine. Most of the breakaway region's population of 470,000 speaks Russian, although residents identify themselves as ethnically Moldovan, Ukrainian or Russian.

Moves to make Moldovan Moldova's official language in 1989, when it still was part of the Soviet Union, alarmed people in Trans-Dniester. The region declared independence in 1990 and clashes broke out. Fighting intensified in March 1992 and lasted until a July cease-fire; more than 700 people are estimated to have died in the conflict.

As part of the cease-fire agreement, a contingent of Russian troops stayed in Trans-Dniester as nominal peacekeepers. Since then, the region has insisted it is not part of Moldova, which declared independence in 1991.

Trans-Dniester has retained many Soviet ways and iconography, including using the hammer-and-sickle image on its flag. But it has remained generally peaceful, and some tourists come to relish the anachronisms.

WHAT HAPPENED THERE THIS WEEK?

Explosions rocked the headquarters of the region's state security ministry on Monday. The building reportedly was empty due to the Orthodox Easter holiday, and no casualties were reported. Officials said the attack was committed with rocket-propelled grenades. Local media showed what appeared to be firing tubes lying on a street.

On Tuesday morning, a pair of explosions at a broadcasting facility knocked two powerful antennas out of service. No claims of responsibility for the attacks have been made.

Trans-Dniester’s president, Vadim Krasnoselsky, called Tuesday for imposing anti-terrorist security measures at a “red level” for 15 days, including setting up blockposts at the entrances to cities.

The United States has warned amid the war in Ukraine that Russia could launch “false-flag” attacks in nearby nations as a pretext for sending in troops.

DOES RUSSIA HAVE AMBITIONS IN THE REGION?

Russia does not recognize Trans-Dniester as independent, as it does with other breakaway areas, such as South Ossetia, Abkhazia and the eastern Ukrainian regions of Donetsk and Luhansk.

It recognition of those areas came either after Russia and Georgia fought a 2008 war or as justification for Moscow's February invasion of Ukraine. An outburst of fighting in Trans-Dniester could change the Kremlin's political calculus; Russia's security policy states it has the right to protect ethnic Russian populations throughout the world.

A senior Russian military official, Rustam Minnekayev, said last week that Russian forces were aiming to take full control of southern Ukraine, saying such a move would also open a land corridor between Russia and Trans-Dniester.

Achieving that military objective would require significant battles to capture Ukraine's Black Sea coast, including the major port city of Odesa. Russian soldiers would surely encounter enormous resistance. The Russian contingent in Trans-Dniester is focused on guarding ammunition and warehouses, and its fitness for combat is uncertain.

Moldova is constitutionally neutral, so Russia could not cite the country seeking to join NATO to justify an invasion, as Russian President Vladimir Putin did with Ukraine. But expanding to Moldova would give Russia a presence next to NATO member Romania.

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