MOSCOW (AP) — Russian President Vladimir Putin hosted the leader of Belarus Friday for another round of difficult talks on closer integration amid mounting Russian economic pressure on its ex-Soviet ally.

Belarusian President Alexander Lukashenko has accused the Kremlin of flouting its obligations on energy supplies while trying to strong-arm him into a closer alliance.

The two leaders smiled broadly but didn't make any remarks as they sat down for talks at Putin's residence in Russia's Black Sea resort of Sochi.

The Kremlin has argued that Belarus, which relies on Russia for most of its energy needs, should accept greater economic integration if it wants to continue receiving Russian resources at subsidized prices.

Putin and Lukashenko met twice in December but failed to resolve their differences, resulting in Russia cutting oil supplies to Belarus at the start of this year.

The transit shipments of Russian crude to Europe via Belarus have continued unimpeded, but the Belarusian oil refineries have been reduced to a minimum capacity, depriving the country from a major source of income. In the past, Belarus has cashed in on exports of petroleum products made from cheap Russian oil.

Earlier this week, Lukashenko boasted about warming ties with the United States in an apparent bid to win concessions from Russia.