Bulgaria's foreign ministry says Belarus President Alexander Lukashenko has promised to release all political prisoners within a month and a half.

The ministry made the announcement Thursday, saying Bulgarian Foreign Minister Nikolai Mladenov met with Mr. Lukashenko in the Belarusian capital, Minsk, last week.

There was no immediate comment from Belarus' government. But in a letter to his European Union colleagues, Mladenov said Mr. Lukashenko promised to release four prisoners by the end of this week and the remaining political activists by the beginning of October.

In the letter, Mladenov said the Belarusian leader also promised to call for a roundtable discussion with the opposition on the country's future.

Analysts say President Lukashenko is seeking to improve strained relations with the EU, which along with the United States has imposed numerous sanctions against his authoritarian government.

Belarus also is facing economic turmoil that forced it to sharply devalue its national currency.