A United Nations fact-finding mission is visiting Sudan's Darfur region to assess whether the government is keeping promises to improve security. They will present their findings by the end of the month - the deadline the Security Council has given Sudan to make improvements or face sanctions. Three UN teams, accompanied by Sudanese officials are taking part. Some one million people have fled their homes and 50,000 died in the violence leading to a major humanitarian crisis. The UN's special envoy to Sudan, Jan Pronk, says Sudan has taken some positive steps. But he remains concerned about the safety of the vast numbers of internally displaced people in Darfur who fear attacks by the pro-government Arab militia known as the Janjaweed. "We are coming very close to the moment of assessment. The clock is ticking," Mr Pronk said on the eve of his visit. "The responsibility is for the authorities in Khartoum not only to make promises but to implement the promises... If not, the international community has to consider what is necessary," he warned. A senior Sudanese government official said they were confident the UN would decide not to impose sanctions when it meets next week to discuss the crisis. Najib Wahhab, Sudan's State Minister for Foreign Affairs, said Khartoum had complied with international agreements on Darfur, and was willing to abide by the terms of a UN Security Council resolution. "We don't like it, but we are going to implement the measures that are contained in it," he told the press. Mr Wahhab, attending peace talks in Abuja, said he believed security in the area had improved. "We can't say all of Darfur is safe, but we have made very good beginnings." Two rebel groups in the arid region rose up against the government some 18 months ago, demanding greater access to resources. Khartoum denies it used the Janjaweed to quell an uprising by Darfur rebel groups last year.