The prime minister has pledged to keep "a very close watch" on the ongoing humanitarian disaster in Sudan.

Answering questions in the Commons on Wednesday, Tony Blair said he was speaking "literally every day" to senior figures in a bid to tackle the refugee crisis in the Darfur region.

Charles Kennedy welcomed the additional £28 million in direct assistance the government has recently given to the aid effort in Sudan.

The Liberal Democrat leader asked Blair "what scope he sees for further practical steps, as millions of Sudanese are facing starvation".

Blair replied that ministers are trying to ensure "aid gets through to the people who need it most" and are applying pressure on the Khartoum government to cut off support for the militias who have sparked the crisis by forcing people to leave their homes.

Kennedy said the "international community must recognise the absolute sense of urgency".

He argued that 60 African Union monitors and 300 troops were inadequate in an area the size of France.

Kennedy also warned of the potential for "the obscenity of another Rwanda".

The prime minister assured him that he was "continuing to monitor the situation very carefully".

He revealed that he is speaking to international counterparts on a daily basis and has twice spoken to UN secretary general Kofi Annan on the issue.

"We will rule absolutely nothing out in this situation," Blair said. "We will continue to keep a very close watch."

Concern at the situation in Sudan has escalated in recent days after heavy rain began to fall in the region and reports emerged of continuing violence and worsening food shortages.