However, rebel groups on Friday said Sudanese warplanes had bombed targets in the east of the country for a second day, wounding several civilians in a region hit by recent fighting between the army and militia.
Sudan's military - already under pressure for tactics including aerial attacks in the western region of Darfur - confirmed "search operations" were under way in the east but denied any bombardment was taking place.
A senior Sudanese armed forces official said search operations were under way in the Dolab Yay, south of Tokar.
"We are using aircraft for these operations," Asswami Khaled Sabr said. "We are undertaking the operations to see where the rebel forces are. There is no bombing."
Aid groups too could not confirm the rebels' claim of bombings.
Fergus Thomas, a field coordinator in northeast Sudan for the US-based International Rescue Committee (IRC), said, however, that rebels had appeared elated following their attacks on government bases in previous days.
Fighting broke out in eastern
Sudan at the weekend
Thomas was referring to fighting that broke out in the east at the weekend near Tokar, when rebel Eastern Front fighters said they destroyed three government garrisons and captured 20 government troops.
"As far as I could tell the attacks were hit and run," he said. "There's a sense of revelry in the rebel-controlled area. People have been slaughtering camels which is rare."
Thomas, who travelled from the rebel-held area to Asmara in the past 24 hours, said he had no word on the alleged bombing.
The rebels however claimed that bombing was on. "Today they are bombing," said Salah Barqueen, spokesman of the Eastern Front group, in neighbouring Eritrea on Friday.
"It is a matter of revenge. It is punishment for the citizens," Barqueen added, saying Khartoum appeared to be retaliating for raids the rebels say they staged on army camps this week.
"They are using the same (method) as they used in Darfur," he added, referring to the region where a separate war has cost tens of thousands of lives since 2003.
"Civilians take all the punishment - their houses, their livestock. Many people have been displaced."
Analysts fear eastern Sudan could become the next battleground in the oil-producing nation, where the Darfur conflict has brought international condemnation and a
"Civilians take all the punishment - their houses, their livestock. Many people have been displaced"
Eastern Front rebel group
21-year-old war in the south only ended a few months ago.
Barqueen said the bombing took place in the Barka Valley west of Tokar, a town 120km south of Port Sudan on the Red Sea.
The eastern rebels have held a small piece of territory just next door to Eritrea in eastern Sudan since the late 1990s.
The Front has friendly ties with rebel groups in Darfur and former rebels in the south, whose complaints about neglect of their respective areas by Khartoum are similar.
Taisier Ali, secretary-general of the Sudan Alliance Forces, a Sudanese opposition party, said the last attack by Sudanese government warplanes on civilians in the east was in May 2000.
"Definitely that would be considered as an escalation," he said when informed of the rebels' claim of bombing around Tokar.
In a separate development, Sudan's Foreign Minister Mustafa
Osman Ismail, visiting the US on Friday, said that US Secretary of State Condoleezza Rice had agreed to consider the possibility of lifting sanctions imposed on the northeast African state.
"Secretary Rice told me, she promised me, that she is going to start looking at it," Ismail told reporters at the State Department.
State Department officials were not available for comment.
Rice did not speak to reporters.