The European Union has urged the United Nations to threaten Sudan with sanctions over the violence in Darfur.
About a million have been forced from their homes
A statement by 25 EU foreign ministers said the UN should pass a resolution if the Sudanese government did not rein in Arab militias blamed for atrocities.
The Security Council is debating a US-sponsored resolution imposing sanctions on the militias and their sponsors.
Sudan's foreign minister criticised the EU move as "unbalanced", and said: "We don't need threatening."
About a million people have fled their homes and thousands have been killed since the conflict started last year.
The UN has described Darfur as the world's worst humanitarian crisis.
Thousands of refugees will die of disease and starvation unless more aid is sent urgently, the relief organisation Medecins Sans Frontieres warned on Monday.
The pro-government militias - or Janjaweed - are accused of ethnic cleansing against the black African population.
The Sudanese government denies backing the militiamen. In early July it promised to disarm them.
The EU ministers appealed to the Security Council "to pass a resolution with a view to taking further actions, including imposing sanctions, in case the government of Sudan does not immediately fulfil its obligations and commitments".
"There is no indication that the government of Sudan has taken real and provable steps to disarm and neutralise the armed militia, including the Janjaweed," their statement after talks in Brussels said.
Dutch Foreign Minister Bernard Bot - whose country currently holds the EU presidency - said the Sudanese government were aware that "the threat of sanctions is imminent if they don't comply with the obligations".
"We will monitor very carefully.... every day, every week the progress in the field. In that way we can see at what moment further measures have to be taken," Mr Bot told reporters after the talks.
The EU also agreed to send extra funds worth more than $30m to ease the humanitarian crisis.
Ministers urged the Sudanese government to admit more aid workers to provide emergency food and shelter for the people displaced in the region.
Sudanese President Omar al-Bashir has called an emergency cabinet meeting to discuss Darfur on Tuesday.
Foreign Minister Mustafa Osman Ismail urged the EU to support the government.
"The pressure toward the government will have a negative effect," Mr Ismail said during a visit in Turkey.
"These rebels will always perceive this pressure to be on the government alone and let it continue."
Disease and starvation
"There is the potential for significant numbers of deaths due to malnutrition or epidemics in the refugee camps, where conditions have hardly improved at all despite increased international attention," said MSF president Rowan Gillies.
"The urgency of response is not adequate. The scale of response is not adequate," Mr Gillies said.
On Monday, an aid flight organised by UK aid agency Oxfam and carrying 30 tons of water and sanitation equipment landed in Nyala, southern Darfur.
Children are dying from malnutrition in the camps
In neighbouring Chad, aid workers are continuing efforts to distribute supplies in two camps where operations were suspended for several days last week because of violence.
Relief agencies say more international help is required. France, which has an air base in the Chadian capital, Ndjamena, is coming under pressure to do more.
French Foreign Minister Michel Barnier is beginning a three-day visit that will include both Chad and Sudan.
He is expected to try to exert more influence on the Sudanese government to resolve the conflict.