African Union Chairwoman Nkosazana Dlamini-Zuma said she was frustrated following attacks in North and South Kordofan states.
Sudanese rebel forces launched attacks last weekend along the border of Sudan and South Sudan. The independent Sudan Tribune reports at least nine Sudanese policemen died in the fighting.
Dlamini-Zuma said in a statement that all parties to the conflict are called on to "exercise maximum restraint and allow the political leadership to work through direct talks to reach a comprehensive resolution" to the crisis.
Weekend attacks coincided with the start in Ethiopia of direct talks between rebel forces and the Sudanese government.
Catherine Ashton, the foreign policy chief for the European Union, condemned the most recent attacks but expressed hope the incident wouldn't undermine the peace initiatives in Addis Ababa. Both parties said they'd continue negotiations in May.
Ashton urged both sides "to commit to resume negotiations in good faith in order to agree on an immediate cease-fire, safe and unhindered humanitarian access, and on a comprehensive solution to the conflict," a statement issued through her spokesman said.