Uganda has accused the U.S. ambassador in the country of seeking to subvert last week's presidential election.
That's after the American embassy in Kampala said Nathalie E. Brown was prevented from visiting opposition leader Bobi Wine at his home, which has been surrounded by security forces since the vote.
President Yoweri Museveni, in power since 1986, was declared winner of the poll though Wine and his National Unity Platform want to legally challenge the results.
Museveni claims the election may turn out to be the most "cheating free" in Uganda's history.
The U.S. embassy has said the vote was tainted by harassment of opposition candidates, suppression of media and rights advocates and a nationwide internet shutdown.
It said Ambassador Brown visited Wine's compound to try and check on his health and safety.
But government spokesman Ofwono Opondo claimed, without providing evidence, that Ambassador Brown had a track record of causing trouble in countries where she worked.
"But what she has been trying to do blatantly is to meddle in Uganda's internal politics, particularly elections, to subvert our elections, and the will of the people."
The public rebuke to the United States is relatively unusual as the two nations are allies.
Washington supports Ugandan soldiers serving in an African Union peacekeeping mission in Somalia and has donated about $1.5 billion to Uganda's health sector in the past three years.
Troops have prevented Wine - real name Robert Kyagulanyi - from leaving his home since he returned from voting on Thursday (January 14).
On Tuesday (January 19) he said he and his wife have run out of food, and milk for their niece. Her father has been refused entry to collect the 18-month-old, Wine wrote on Twitter.
A police spokesman said a motorcycle courier had delivered food to Wine's house each day.
On Tuesday Wine's lawyers filed a petition in the high court challenging the legality of detaining Wine and his wife without charge.