British police said they have arrested a man who launched a sledgehammer attack on the security gates at the entrance of Downing Street early Friday morning.

The man, whose identity was not immediately known, was held at the scene at 0520 GMT for causing criminal damage and taken to a central London police station, Scotland Yard said.

The nearby road was sealed off and searched as a precaution butre-opened after about one and half hour.

Police believed the incident was not terrorist-related.

"This is not being treated as a terrorist incident. A more likely explanation is a small protest or mental illness," a Scotland Yard spokesman said.

Downing Street, the residence of British Prime Minister Tony Blair and Chancellor of Exchequer Gordon Brown, has been the target for protests in the recent past.

In February this year a group of demonstrators were arrested for throwing white paint at the gates of Downing Street.

Source: Xinhua