Sudan's air raids on South Sudan killed at least 16 civilians and wounded 34, UN officials told the UN Security Council, which condemned the attacks.
The 15-member council made a new call for a ceasefire between the rival states at the end of hastily-called talks on the surging conflict.
Bombing raids on South Sudan's Unity state have followed the South's withdrawal from the disputed oil town of Heglig.
The UN Mission in South Sudan (UNMISS) "confirmed that at least 16 civilians have been killed and 34 injured in Unity state from aerial bombardments in addition to significant damage to infrastructure," US ambassador Susan Rice told reporters.
Rice, speaking as the council president for April, said members were also told there had been Sudanese "incursions" into Unity state.
The council "welcomed" the withdrawal from Heglig by South Sudan's forces, "demanded an immediate halt to aerial bombardments by the Sudanese Armed Forces and urged an immediate ceasefire and a return to the negotiating table," Rice said.
The Security Council also strongly condemned an attack on UN-African Union peacekeepers in Darfur, which left one Togolese dead and three others wounded, Rice said.
"They called on the government of Sudan to bring the perpetrators to justice and stressed that there must be an end to impunity for those who attack peacekeepers," the envoy said.
{{/usCountry}}"They called on the government of Sudan to bring the perpetrators to justice and stressed that there must be an end to impunity for those who attack peacekeepers," the envoy said.
{{/usCountry}}Togolese police in the force were attacked by unidentified gunmen on Friday as they were returning to their base in Murnei, West Darfur state, the UN said.