Russian President Vladimir Putin signed an order on Wednesday further expanding the number of Ukrainian citizens who can apply for fast-track Russian passports.

Moscow made the move ahead of a Ukrainian parliamentary election on Sunday, when a Russia-friendly party may become the strongest competitor of the more popular Servant of the People party, led by new president Volodymyr Zelenskiy, according to opinion polls.

The new order, published on the Kremlin website, amended Putin's earlier decree, which made it simpler for residents of separatist-controlled eastern Ukraine to apply for Russian passports.

According to the new document, residents of the neighbouring government-controlled parts of east-Ukrainian Donetsk and Luhansk regions can also use this procedure if they were registered as permanently living there as of April 2014, when the conflict started.