The United States and the European Union have stepped up calls for Sudan to let international troops in to support African Union forces in Darfur amid growing talk of sanctions on Khartoum.
The calls followed warnings from London and Washington that Sudan could face measures such as imposition of a no-fly zone over its vast west if it did not agree to such a force soon.
"Time is of the essence in a dire humanitarian situation," EU leaders said in a joint communique issued after talks on Darfur at a European summit in Brussels.
"(The EU) strongly urges the government of Sudan to give its unequivocal consent to the implementation of the UN support package for the AU mission in Sudan in its entirety."
The UN support package is due to gradually turn the AU mission into a hybrid UN-AU operation. Sudan has so far refused to allow an international force to go to Darfur to end three years of fighting that has killed over 200,000 people.
After talks in Brussels with EU foreign policy chief Javier Solana and NATO Secretary-General Jaap de Hoop Scheffer, US special envoy to Sudan Andrew Natsios also urged Sudan to unblock the UN proposals.
"If we cannot get that resolved then we have a big problem," he told reporters of Sudan's continued resistance, declining to spell out what consequences it would face if it persisted.