Pressure has continued to mount for a solution to the humanitarian disaster in the Darfur region of Sudan.

Visiting a refugee camp in northern Darfur on Tuesday, foreign secretary Jack Straw had warned that progress was needed in the latest round of peace talks.

Discussions between rebel groups and the Khartoum government are being held in Nigeria, but the first indications were not hopeful.

Rebel leaders were reported to have rejected plans to restrict armed groups to certain areas of the country.

But campaign groups and the international community are maintaining the pressure for a compromise solution.

The United Nations security council has set a deadline of the end of this month for government action to control the Arab militias responsible for terrorising black African civilians.

It is estimated that more than a million people have fled their homes in the region, leading to a major humanitarian crisis.

Some 200,000 refugees have crossed the border into neighbouring Chad.

Amnesty International said, however, that rather than curbing human rights violations in Darfur the Sudanese government was "gagging" those who speak about the abuses.

"As long as people who want to speak out about these violations are intimidated and arrested, the commitments of the government of Sudan to the international community will remain hollow," said Irene Khan, the campaign group's secretary general.

Further discussion on an "African solution" to the problem were set to take place on Wednesday and Thursday when the British foreign secretary takes part in bi-lateral talks with the South African government.

Straw has backed an increase in African troops policing the Darfur region.