Brent crude fell $2 towards $113 on Friday as a quiet start to the planned 'day of rage' in Saudi Arabia eased concern that unrest would spread in the world's top oil exporter, prompting investors to unwind positions.

ICE April Brent crude fell $2 to $113.43 by 0721 GMT. It touched a 2-1/2-year high of $119.79 a barrel on Feb. 24 as protests flared in Libya, disrupting oil output.

'We are getting a much needed correction; unless this day of rage really explodes, the momentum is on the downside,' said Tony Nunan, a risk manager with Tokyo-based Mitsubishi Corp.

'I think it's gone a little bit too far. Eventually it should go to $90 for WTI and $100 for Brent.'

Friday's price decline accelerated after a massive 8.9 magnitude quake hit northeast Japan, triggering a 10-metre tsunami that swept away everything in its path, including houses, cars, farm buildings on fire and boats.

'Crude was already selling off and this adds to the pessimism,' said David Cohen, director of Asian economic forecasting at Action Economics.

'Markets had been nervous about the Middle East, and this serves as an opportunity for a correction. There will be some impact on capacity because of the damage to the refineries.'

JX Nippon Oil & Energy Corp, Japan's top refiner, has halted operations of three refineries in Sendai, Kashima and Negishi after the tremor, Jiji News said.

Saudi Arabia's capital was quiet on Friday ahead of a planned day of demonstrations that will test whether activists calling for reform online will succeed in taking their protests to the streets.

Police fired in the air to disperse protesters on Thursday, and three people were injured in the melee.

Brent touched a 2-1/2-year high of $119.79 on February 24 as protests flared in Libya, disrupting oil output.-Reuters