Zimbabweans voted Saturday for a key referendum on a new constitution that limits presidential terms for the first time in the African nation.

Robert Mugabe, 89, has been in power for decades, first serving as prime minister in 1980 and taking over as president seven years later.

"This is a Zimbabwean document to replace a British one. That is why I voted for it," said Babra Mheno, 34, a university student, referring to the nation's former colonial rulers.

If approved, which is highly likely, the constitution will give more powers to the parliament and limit the president's. It also introduces a two-term limit of five years each for a president.