The European Commission described Zimbabwe's presidential run-off on Friday as a "sham" and said it did not recognise the election or its outcome as legitimate.

"The European Commission, like the U.N., does not consider this election legitimate or valid," a spokeswoman for the EU executive said of President Robert Mugabe's decision to press on with the vote despite the withdrawal of his main opponent, Morgan Tsvangirai, citing intimidation.

"Today's election is a sham, the election is hollow and its result will be equally hollow and meaningless." spokeswoman Krisztina Nagy told a regular briefing, adding the electoral process had been "dominated by a systematic government-led campaign of violence and intimidation".

Zimbabweans voted slowly in the one-candidate election on Friday after Mugabe defied world condemnation and calls to postpone the vote.

At a summit last week, EU leaders threatened more sanctions against Zimbabwe after violence scarred the run-up to the vote.

Existing EU sanctions include an arms embargo, visa bans and freezing of assets on more than 100 officials including Mugabe.

A European Parliament committee called this week for an opposition-led unity government in Zimbabwe and for EU states to tighten sanctions on Mugabe's government if it rejected mediation.

Separately, Italian Foreign Minister Franco Frattini said he would ask France, which takes over the rotating EU presidency on July 1, to begin talks on the possibility of recalling EU ambassadors from Zimbabwe.