Ashton hailed the elections as "an important moment" in the country's peace process and welcomed the fact that they were "largely peaceful."

The European Union sent its largest ever election monitoring mission to the polls, which closed last Thursday, and it was their observations which raised Ashton's concern.

"Although these elections have been particularly complex, I note with concern the deficiencies as identified already by the EU EOM (Election Observation Mission) and other observers," she said in a statement.

"It is important that the noted shortcomings are urgently addressed," particularly in view of a planned referendum in January 2011 on self-determination in South Sudan, Ashton added.

Sudan's national election commission said that results from the first multi-party election in 24 years, originally expected on Tuesday, would be delayed.

The election is likely to see the return to power of President Omar al-Beshir, who seized control of Africa's largest country in a military coup backed by Islamists in 1989.

International observers from the European Union and the Carter Center said on Saturday that the polls had failed to reach international standards.

Sudan's first multi-party elections since 1986 called on some 16 million voters to choose their president, legislative and local representatives. Southerners also voted for a president of their autonomous region.

Ahead of polling, two key Beshir challengers -- the Umma Party's Sadiq al-Mahdi and Yasser Arman of the former rebel Sudan People's Liberation Movement (SPLM) -- withdrew, paving the way for a near-certain Beshir victory.

In 2005, the SPLM signed a deal with the Khartoum government to end Africa's longest-running civil war. The peace deal provided for the elections and the independence referendum.

"Efforts to find a durable inclusive political solution to the protracted conflict in Darfur must be increased," said Ashton.

"The EU stands ready to assist the Sudanese people in these important moments," she added.

By SAPA