HARARE, March 5 (Reuters) - Armed riot police broke up a meeting called by Zimbabwe's Prime Minister Morgan Tsvangirai on Tuesday, his spokesman said, raising tensions in a fragile power-sharing government ahead of elections this year.
Former opposition chief Tsvangirai went into government with his rival President Robert Mugabe after a violent and disputed vote in 2008.
The two have had a stormy relationship and Tsvangirai has accused Mugabe of using the security services to intimidate his supporters in the past - charges Mugabe denies.
Tsvangirai's spokesman Luke Tamborinyoka said around 40 heavily armed riot police arrived at public meeting about a proposed new constitution in a Harare township on Tuesday evening and ordered the audience to leave before the prime minister arrived.
The officers said the debate had not been authorised, said Tamborinyoka - all public meetings have to be cleared by the police by law.
"It is a campaign for a constitution that both parties are supporting. We have the same message. Imagine during the election campaign when we have differing messages?," he said, referring to presidential and parliamentary votes expected in July.
Tamborinyoka said Tsvangirai's officials had informed the police about the meeting.
Tsvangirai and Mugabe have agreed on the terms of a new constitution to strengthen the powers of parliament and curb those of the president, which will be put to a national referendum on March 16.
No one was immediately available to comment from the police.
Mugabe has been in power since Zimbabwe's independence in 1980. (Reporting by Nelson Banya; Editing by Andrew Heavens)