Kenya's prime minister is in a stable condition after doctors made a hole in his head to relieve pressure building on the outside of his brain.
Prime Minister Raila Odinga, 65, will remain in the hospital for the next five days, neurosurgeon Dr. Oluoch Olunya said.
"I would like to assure the country that he is actually well. The headache that he had yesterday has all been cleared," said Dr Olunya.
He added that doctors had to open a hole in Odinga's skull to drain the fluid on Monday.
"Suffice it is to say drainage was carried out, when you talk about surgery it is just a release by opening a small opening at the skull," Olunya said.
Mr Odinga was admitted to the hospital after reporting feelings of exhaustion. Officials had said the prime minister was suffering from fatigue. A statement from Nairobi Hospital called the procedure doctors carried out to relieve the pressure "minor".
Mr Odinga became prime minister when he signed a power-sharing deal with President Mwai Kibaki to end violence following Kenya's disputed December 2007 presidential election. More than 1,000 people were killed in the post-election violence.
The prime minister's doctor said the build-up of pressure occurred after Mr Odinga banged his head in one of his vehicles three weeks ago.
Mr Odinga's doctors did not answer questions from reporters and did not specify the exact condition affecting him. One possibility is hydrocephalus, a condition where excessive fluid builds up on the brain. If left untreated, symptoms of the condition include cognitive problems and difficulty walking, according to the website of the Hydrocephalus Association.
The last time Odinga was hospitalized was in 2008 when he underwent an eye operation in Germany.