Russian rouble pulls back from one-week low against dollar

May 28 (Reuters) - The Russian rouble strengthened beyond the 80 mark to the dollar on Wednesday, pulling back from a one-week low it hit in early trade, with market players keeping an eye on geopolitical developments.

The United States and Russia quarrelled in public on Wednesday over the intensifying war in Ukraine as U.S. President Donald Trump warned that his counterpart Vladimir Putin was "playing with fire" and Moscow massed 50,000 troops near a Ukrainian region.

By 0813 GMT, the rouble RUB= was up 0.6% at 79.75 per U.S. dollar, LSEG data based on over-the-counter quotes showed. The Russian currency hit a one-week low of 80.50 earlier in the session.

The rouble has strengthened by over 40% against the dollar this year, a rise analysts have attributed to the easing of geopolitical tensions - mainly with Trump's administration - and the central bank's tight monetary policy, which has reduced demand for foreign currency.

Russia's government last week said it had extended requirements for major exporters to sell a proportion of their foreign currency earnings until the end of April 2026, buttressing the rouble.

Those restrictions, the Bank of Russia's 21% key interest rate and month-end tax payments, which usually see exporters convert their foreign currency earnings into roubles to pay local liabilities, are all supporting the rouble.

Against the Chinese yuan, the rouble was up 0.4% at 11.06 on the Moscow Stock Exchange. Russia's central bank uses yuan for foreign exchange interventions, and it is the most-traded foreign currency in Russia.

The rouble is set to lose tax payments support from tomorrow, said Bogdan Zvarich of Promsvyazbank, which will likely prevent it from strengthening past 11 to the yuan, while continued geopolitical uncertainty and low oil prices could see it start to weaken.

Brent crude oil LCOc1, a global benchmark for Russia's main export, was up 0.5% at $64.42 a barrel.