The four have targeted Belarus since President Alexander Lukashenko won yet another term in office last year after elections that the West and other observers say were fraudulent, and over the security crackdown on peaceful protestors that followed.

The U.S. State Department said the U.S. Treasury has ``identified three aircraft as blocked property and designated 32 individuals and entities, including Belarusian state-owned enterprises, government officials, and other persons, who support the regime and facilitate its repression.''

The EU, meanwhile, imposed travel bans and asset freezes on 17 more people, including senior border guard and military officials, government representatives and judges.

The measures also hit air carriers _ including state carrier Belavia _ and travel groups accused by the EU of helping to bring migrants to Belarus with the aim of helping them cross into the 27-country bloc, chiefly through Poland, Lithuania and Latvia.

Britain said had imposed sanctions ``on eight Belarusian individuals responsible for repression and human rights violations.'' It also froze the assets of OJSC Belaruskali, one of the world's largest producers of potash fertilizer, which is a major source of revenue for the Belarus government.