WASHINGTON (CNN) -- The United States is cutting the size of its embassy staff in Belarus amid a diplomatic dispute with that country's government, the U.S. State Department said Monday.

"The United States will, with great regret, reduce the number of American staff at our embassy in Minsk by almost half, at the insistence of the Government of Belarus," State Department spokesman Sean McCormack said in a statement.

The State Department did not announce the number of cuts, but Andrei Popov, press secretary of the Belarussian Foreign Ministry, said staffing at the U.S. Embassy would be equal with the Belarussian embassy in Washington, which has 18 diplomats, Russia's ITAR-TASS news agency reported.

"Visa processing in Belarus is temporarily suspended," McCormack said.

Relations between the United States and Belarus have been tempestuous for the last decade, but they deteriorated quickly over the last month.

On March 7, Belarus recalled its ambassador to the United States and suggested the U.S. ambassador to Belarus leave that country. Belarus acted to protest U.S. sanctions against Belarussian oil monopoly Belneftekhim.

On March 12, U.S. Ambassador to Belarus Karen Stewart returned to Washington.

Then, on March 17, the Belorussian Foreign Ministry gave an "urgent recommendation" to Jonathan Moore, deputy chief of mission at the U.S. Embassy in Minsk, that the United States reduce the size of its embassy staff.

"The unfortunate actions by the Belarus authorities demonstrate that Belarus has taken a path of confrontation and isolation rather than a path of engagement and democratic reform," McCormack said.

"We would like a different relationship with Belarus, but that can only happen when the government of Belarus shows commitment to respect for human rights and fundamental freedoms."

Washington has been pushing for the release of Alexander Kozulin, the runner-up in the 2006 presidential election in Belarus. He received a five-year prison term for leading demonstrations against election results that international observers said were flawed.

The sanctions against Belneftekhim were meant to pressure Minsk to release Kozulin, as well as several other political prisoners.

The United States has long been critical of the iron-fisted rule of President Alexander Lukashenko, lending its support to the opposition and barring entry into the United States to members of the Belarussian government. He took office in 1995 and quickly consolidated power.

In 2005, U.S. Secretary of State Condoleezza Rice called Belarus the last "outpost of tyranny" in Europe. A year earlier, the U.S. Congress approved American assistance for democratic political parties, non-governmental organizations and media and barred all non-humanitarian aid to the government. E-mail to a friend

All About Belarus • Alexander Lukashenko • Condoleezza Rice