(CNN) -- U.S. President George Bush railed against the government of Zimbabwean president Robert Mugabe Monday, calling intimidation of opposition figures "deplorable."
Leading opposition figure Artur Mutambara was arrested following his criticism of President Robert Mugabe.
"The continued use of government-sponsored violence in Zimbabwe, including unwarranted arrests and intimidation of opposition figures, to prevent the Movement for Democratic Change from campaigning freely ahead of the June 27 presidential runoff election is deplorable," Bush said in a statement released by the U.S. Embassy in neighboring South Africa.
Zimbabwean authorities Sunday arrested an opposition leader on charges stemming from his criticism of the government and its handling of the recent presidential election, an official with the opposition Movement for Democratic Change told CNN.
Police in Harare surrounded the house of student activist-turned-opposition politician Arthur Mutambara and arrested him on charges of contempt of court and publishing falsehoods, MDC official Romualdo Mavedzenge said.
While Zimbabwe authorities have arrested dozens of MDC supporters and activists over the past two months, Mavedzenge said "this is the highest profile MDC official (arrested) since the March 29 election."
Mutambara is president of an MDC faction that split from the main party headed by Morgan Tsvangirai.
After Tsvangirai's party won the majority of seats in parliament, the two leaders agreed to join forces in parliament under Mutambara's leadership.
Both charges stem from an opinion piece written by Mutambara in which he criticized President Robert Mugabe for the way the March 29 elections were handled. Raphael Khumalo, chief executive of The Sunday Standard, which published the article, was arrested last month on charges of publishing falsehoods.
Bush said Mugabe's government is failing on multiple levels.
"We call on the regime to immediately halt all attacks and to permit freedom of assembly, freedom of speech, and access to the media," Bush said.
"We urge the Southern African Development Community, the African Union, the United Nations, and other international organizations to blanket the country with election and human rights monitors immediately."
Zimbabwe's election commission said Tsvangirai won the March presidential election, but didn't win a majority of the vote, forcing this month's vote.
The MDC contested the results, saying Tsvangirai won outright, but decided to take part in the runoff and not cede the election to Mugabe.