Transnistria, which borders war-stricken Ukraine to the east, has maintained autonomy from Moldova for three decades with support from Russia, which has more than a thousand troops stationed there since a brief war in 1992.
Since Moscow began its full-scale assault on Ukraine, Chișinău has been concerned the Kremlin could use Transnistria to open a new front in the south-west, in the direction of Odesa.
The request for Russia to help Transnistria's economy withstand Moldovan "pressure" was made after a meeting of hundreds of officials in the unrecognised region.
The resolution came a day before the Russian president, Vladimir Putin, on Thursday makes his annual address to Russian lawmakers and as Ukraine suffers setbacks on the battlefield. There are suggestions Putin might bring up the Transnistrian request in his speech and express support for the region.
Moldova's pro-European government dismissed the appeal as a propaganda event to gain headlines.
The region, long seen as a potential flashpoint with Russia in Europe, held a "congress of deputies of all levels" after Moldova said it would require Transnistrian companies to pay import duties to the central budget from January.
At the meeting, the congress passed a resolution saying it would appeal to both houses of Russia's parliament "with a request to implement measures to protect [Transnistria] in the face of increasing pressure from Moldova".
Russian officials responded by saying that one of its "priorities" was to protect the thin sliver of land, which has been de facto controlled by pro-Russian forces since the collapse of the Soviet Union but is internationally recognised as part of Moldova.
US state department spokesperson Matthew Miller said on Wednesday: "Given Russia's increasingly aggressive role in Europe, we are watching Russia's actions in Transnistria and the broader situation there very closely."
After Russia's full-scale invasion of Ukraine in 2022, tensions surged around the separatist region, which says it has 220,000 Russian citizens. Relations between Moldova and Russia have also frayed as the government in Chișinău has steered a pro-European course.
Comment: Mustn't forget to say "full-scale invasion" even though Russia has committed only a fraction of its military to the Special Military Operation. If Russia ever went 'full-scale', there would be nothing left to call Ukraine.
Moldova's president, Maia Sandu, in Albania for a summit of south-east European countries, said her country remained committed to a peaceful resolution of the Transnistrian conflict. "What the government is doing today is making small steps for the economic reintegration of the country," she said.
Polish prime minister Donald Tusk said tensions in Transnistria were dangerous for the region. The problem "is not a new one", he said, adding that the "threat of Russian intervention or at least some provocation there is something permanent".
The call for help from Moscow has fuelled comparisons with February 2022, when Russian-backed militants in eastern Ukraine called for protection against what they said were relentless attacks and shelling by Kyiv's forces.
Comment: Transnistria saw the writing on the wall in 2014, appealing to rejoin Russia even then.