The European Union Sunday demanded Belarus release jailed opposition leader Aleksander Kozulin and supporters who were arrested at a demonstration.
Belarussian Interior Minister Vladimir Naumov said Kozulin had been arrested Saturday for plotting to overthrow the government, the BBC said.
Opposition and international monitors have criticized last Sunday's poll that saw President Alexander Lukashenko take 82.6 percent of the vote, securing his third seven-year term in office.
Last week, EU leaders issued a declaration saying it would "take restrictive measures against those responsible for the violation of international electoral standards." Saturday, a statement said the union was "appalled" and demanded Kozulin and other detainees be freed immediately.
In Washington, White House press spokesman Scott McClellan said on Friday the Bush administration would also apply additional "targeted sanctions" against some governmental officials.