Rwandan troops arrived on Sunday in Sudan's Darfur region– scene of the world's worst humanitarian crisis according to the UN.

The Rwandans arrived by air in Al-Fasher, capital of Northern Darfur state. They will be stationed in six different regions containing large refugee camps, including neighbouring Chad, where thousands of Darfuris have fled in search of security.

The 150 soldiers from Rwanda are expected later this month to be joined by some 150 Nigerian troops in protecting African Union (AU) observers monitoring a ceasefire between government troops and two rebel groups.

Fighting in the western region of Darfur is believed to have claimed up to 50,000 lives in the last 18 months.

Rwandan President Paul Kagame said his country's troops would protect civilians, too. "Our forces will not stand by and watch innocent civilians being hacked to death like the case was here in 1994," Kagame said Saturday, referring to UN troops who did not intervene as a genocide unfolded in Rwanda in 1994.

The Sudanese government welcomed the foreign troops, but continued resisting the growing pressure to accept a larger peacekeeping force of thousands of foreign troops being considered by the African Union and the United Nations.

"The [Sudanese] government reservations are not against the African Union troops, but on [them] being transformed into fully fledged forces, carrying weapons to confront the rebel elements. This will complicate things further," Sudan's Foreign Minister Mustafa Osman Ismail Ismail was quoted by state media.

More than one million Sudanese have fled the fighting in the region, which includes attacks from Arab militia called the Janjaweed.

Some 2.2 million Sudanese are in need of urgent aid, according to the UN.

Human rights groups claim the Janjaweed's campaign against the local African populace amounts to ethnic cleansing and is backed by the Sudanese government.

The U.S. and other countries have also put pressure on Sudan to end the strife in the drought-stricken region.

The government says it is reigning in the militia and blames the rebel groups for causing the security problem.

However, the UN says fighting is continuing in Darfur, as the Janjaweed continue their campaign. The UN has given Khartoum 30 days to act to disarm the militiamen.

Peace talks between the Sudanese government and the rebels are due to begin on Aug. 23 in Nigeria's capital Abuja.