Here's why the region is emerging as a possible new flashpoint of the war in Ukraine.

The mainly Russian-speaking region broke away from then-Soviet Moldova in 1990. After the breakup of the Soviet Union in 1991, pro-Russian separatists fought a bloody war with the Moldovan government forces.

    Russia, which already had troops based there, helped mediate an end to the fighting and the region became one of several "frozen conflicts" in the former Soviet region.

    It has its own currency and army, about 7,500 strong. Sheriff FC, from the region's main city Tiraspol, beat Real Madrid in the group stages of the football Champions League last year.

    No countries recognise the independence of the territory, which lies to Ukraine's southwest and still uses the Soviet Communist hammer-and-sickle as a state emblem.

    Moscow retains 1,500 peacekeepers on the territory as well as 1,400 soldiers guarding a huge arms depot that has been there since the collapse of the Soviet Union.

    The presence of Russian troops has raised fears that Moscow could use Transdniestria as a launchpad for some kind of attack on Ukraine's west, while Kyiv strives to repel Moscow's new offensive in the east.

Russia has already taken control of swathes of Ukraine's south, but in order to get to Transdniestria it would have to pass through Mykolaiv and Odesa, major cities that remain firmly in Ukrainian hands.

Separatist authorities said this week that several blasts knocked out two radio antennae that broadcast in Russian and hit the ministry of state security. They said there had been another attack on a military unit. The separatists have blamed Ukraine, which deny any connection with the incidents.

    Moldovan authorities are on edge and always sensitive to any sign of worsening security in Transdniestria.

    On Tuesday, Moldova's president said the attacks were an attempt by pro-war factions to stoke tensions.