The new leaders of the UK and France have said they are prepared to travel to Sudan's crisis-hit Darfur region to push forward the peace process.

UK Prime Minister Gordon Brown and French President Nicolas Sarkozy made the pledge at a meeting in Paris.

Some 200,000 people have died in Darfur in the past four years and two million have fled their homes, the UN says.

Meanwhile pressure is growing on the Central African Republic to deal with thousands of refugees from Darfur.

'Tougher sanctions'

Mr Brown and Mr Sarkozy were meeting for the first time since they both took office.

Mr Sarkozy said: "People are dying and people are suffering and it must stop."

Darfur conflict map

Mr Brown said the Darfur situation was a "great humanitarian disaster".

The leaders vowed to pursue a UN resolution calling for a joint African Union-United Nations peacekeeping force.

Mr Brown said: "Once the United Nations resolution is passed, we are prepared to go together to Darfur to make sure that the peace process is moving forward."

The prime minister said there should be an immediate ceasefire in the region and if that was not forthcoming there could be a "toughening up of sanctions" against Sudan.

The UN resolution this week ran into opposition from some key nations.

South Africa warned that any talk of sanctions in the draft was "totally unacceptable".

Sudan also said the draft should drop "irrelevant and alien issues" like the threat of sanctions.

Last month, Khartoum agreed to allow the hybrid force into the region after months of pressure from the international community.

A small African Union force has failed to halt the violence.

Militia violence

The conflict began in 2003 after a rebel group began attacking government targets, saying the region was being neglected by Khartoum.

Since then Janjaweed militias have been accused of trying to "cleanse" black Africans from large swathes of territory.

The government admits mobilising "self-defence militias" but denies any links to the Janjaweed.

Meanwhile the crisis has been spreading to the Central African Republic, says BBC correspondent Karen Allen.

The CAR has seen nearly 3,000 refugees arriving in the past few months following air strikes in south Darfur.

Nearby Chad already has more than 200,000 refugees from Darfur.