Top United Nations officials failed to gain Sudan's agreement to allow a technical team to plan the deployment of UN troops to the violent Darfur region as a Security Council deadline expired on Wednesday. The council passed a resolution on Tuesday last week saying Khartoum had to allow a UN assessment team to begin work within a week on the plan to take over from an ill-equipped and struggling African Union force monitoring a shaky truce in the region. The government has refused the team visas. UN Secretary-General Kofi Annan's veteran troubleshooter Lakhdar Brahimi and the world body's peacekeeping chief Hedi Annabi began talks in the capital on Tuesday to break the deadlock but, as the deadline expired, no agreement was reached.