* Vietnam imported 506,400 T of Russian wheat in July-Sept
* Three vessels with Russian wheat unloaded in Vietnam -TASS
* Issue with new export certificates to be resolved soon - Russia (Writes through to focus on comment by Russian regulator)
MOSCOW, Oct 29 (Reuters) - Russia has agreed to provide Vietnam with a list of its wheat exporters for approval, the Russian regulator said on Tuesday, as the two countries try to resolve Vietnamese quality concerns about the Russian crop.
Vietnam has complained that it has found thistle seed in wheat imported from Russia and some other big suppliers and has urged local importers to seek supplies from other countries.
Vietnam slashed its wheat purchases from Russia a year ago after finding imports contained thistle seed, as it fears thistle seed could spread across Vietnam and damage crops.
Earlier this month Vietnam asked Russia's agriculture safety watchdog to temporarily suspend issuing new wheat export certificates for shipments to Vietnam until the issue with thistle seed is resolved.
Last week, officials from the two countries held talks and "the Vietnamese side proposed to introduce certification of Russian exporters in order to regulate the situation with the supply of Russian wheat," the Russian watchdog, Rosselkhoznadzor, said in a statement on Tuesday.
"Rosselkhoznadzor will send a list of companies interested in exporting wheat to the Vietnamese market, specifying the expected amount of supply..."
"These decisions will help to solve the issue in the nearest future," the regulator told Reuters, when asked if the issuance of new export certificates had been resumed.
Russian state news agency TASS reported on Tuesday, citing Deputy Prime Minister Maxim Akimov, that Russia had resumed shipments to Vietnam as three vessels - which were already in the country - were unloaded.
"We have solved this issue, have settled it with the Vietnamese side, the Russian grain has already come to the Vietnamese market," TASS cited Akimov as saying.
"We agreed on increased phytosanitary control over supplies.... The most important thing right now is that three vessels have been unloaded," Akimov told TASS.
Vietnam imported 506,400 tonnes of wheat from Russia, the world's largest wheat exporter, in July-September this year, down from 1 million tonnes in the same period of last year. Vietnam bought 154,200 tonnes in October 2018 and then did not buy any Russian wheat between November 2018 and June 2019. (Reporting by Andrey Kuzmin and Polina Devitt; Editing by Muralikumar Anantharaman/Louise Heavens/Susan Fenton)