Russia could ask its richest citizens to help foot the bill for the annexation of Crimea by paying a "solidarity tax" proposed by a group of lawmakers.

Russian MPs have drawn up a draft law that would increase income tax for people earning more than 1 million rubles ($28,700) a month. The draft bill proposes that they pay up to 30 percent of their earnings compared to the current flat rate of 13 percent.

"The main goal is to support regional budgets and that means also the budget of Russia's new territories," Andrei Krutov, the deputy leading the planned legislation, told Reuters.

His reference to "new territories" made it clear that a key aim of the legislation was to help the government pay for Crimea's absorption into Russia.

The Black Sea peninsula was annexed in March, an action not recognized by Kyiv, U.S. and EU countries.