Cristina Fernandez, the Argentinian president, will undergo surgery to remove a blood clot lodged between her brain and skull that has been causing worrying symptoms, her physician has said.

The president's doctors said on Monday that they had ordered the president to rest for a month after discovering the clot which was pressuring her brain and causing headaches.

In some patients these clots are absorbed back into the body over time, but in this case the situation became urgent
as Fernandez felt a weakness and numbness in her upper left arm on Sunday evening, according to doctors.

"Facing these symptoms, the team decided on surgical intervention," the hospital's doctors said in a statement on Monday.

The surgery involves drilling small holes through the skull to remove old blood.

In a statement released late on Saturday that raised more questions than answers, her doctors attributed the injury to a still unexplained blow to her head she suffered on August 12.

Vice President Amado Boudou addressed the public in a speech, wishing the best for the president but made no mention of any formal delegation of the president's executive powers during her surgery or during her recovery. Boudou is also under investigation for alleged corruption and illegal enrichment.

Transfer of power 

By Monday afternoon no official announcement was made regarding the transfer of power though some Argentine media reported that immediately after his speech, Boudou signed a document formally assuming control of the government.

Speculation regarding the transfer remain as the president's Spokesman, Alfredo Scoccimarro, has not answered lingering questions on the matter.

Argentina's constitution provides for, but does not require, a formal transfer of power in case of health problems, said Daniel Sabsay, a constituional lawyer.

A full medical leave would require Congressional approval, but short of that, "she alone decides, according to the problem she faces and her doctors' advice, if she needs to delegate some powers to the vice president", he told Radio Continental.

The ordeal has meant that Fernandez will be off the campaign trail three weeks before elections, potentially loosening the ruling party's hold on Congress.