"We have communicated ... our astonishment over the US administration's position of seeking to impose sanctions on Sudan and, at the same time, considering normalisation of ties," an official said after a visit by US State Department Adviser for Sudan Charles Snyder.
Sudanese Foreign Ministry official Muhammad Amin al-Qarib said that during his visit Snyder had promised that the draft resolution proposing sanctions would be "mitigated".
He also said the US official had made the normalisation of ties between the two countries conditional on "the establishment of the proposed broad-based transitional national government front and progress in the Darfur crisis".
This is a reference to a national unity government including the ruling National Congress, opposition movements and rebel groups to be set up during the six-year interim period provided for by a recent peace agreement with southern rebels.
"We communicated ... our astonishment over the US administration's position of seeking to impose sanctions on Sudan and, at the same time, considering normalisation of ties"
Muhammad Amin al-Qarib,
Sudanese Foreign Ministry official
Washington has named a new charge d'affaires in Khartoum and taken a number of diplomatic steps to bolster its presence in the country and support peace moves.
But the US State Department also issued a stark warning to Khartoum last week over the violence in Darfur it labels as genocide and proposed new UN sanctions on the African state.
Tens of thousands of people have died after two years of fighting in the western region of Darfur, where the government and militias have been trying to quell a rebellion launched in February 2003.