South Sudan said Saturday it was cancelling planned face-to-face peace talks with Sudan after accusing Khartoum of launching a new air raid on its territory.

"We were left with no choice but to suspend our direct bilateral talks with Sudan," the spokesman for Juba's delegation at the talks in Addis Ababa, Atif Kiir, said.

"You cannot sit with them to negotiate when they are bombing our territory," he added.

"The only negotiations that will happen now will happen through the panel," he said, referring to an African Union mediation panel conducting the talks in the Ethiopian capital.

The negotiations to settle disputes stemming from the South's independence in July last year stalled in April, but resumed in May.

"There was bombing yesterday morning at a place called Rubaker," in northern Bahr el Ghazal, South Sudan's military spokesman Philip Aguer told AFP earlier, adding that "this might have implications because maybe that is the intention of Sudan to bomb us and to stop talking."

Aguer said eight bombs were dropped by Sudanese army Antonov planes.

"Two civilians were wounded -- a man and a woman. They were sleeping in their houses in the villages of Wuer Kil and Wuer Puech", he said.

"Last time they wanted to break off talks in Addis Ababa, they bombed us ... that was on March 26" at a military base in oil-producing Unity state, he added.

The fighting in March led to a new escalation of violence between the two sides and fears of renewed full-blown war.

A new round of talks is due to begin Sunday at African Union headquarters, a week after Sudanese President Omar al-Beshir and his South Sudanese counterpart Salva Kiir exchanged a symbolic handshake at a bloc summit.

Spokesman Atef Kiir said there was "no reflection" of the mood set by the meeting of the two presidents, adding, "we are doing our best"

South Sudanese Communications Minister Barnaba Marial Benjamin commented, "There are people who don't want the talks within the Khartoum regime -- that's why they are bombing us."

The African Union's Peace and Security Council has urged Khartoum and Juba to settle their differences on oil and border demarcation before an August 2 deadline set by the United Nations.

Decades of conflict between the mainly Arab and Muslim north and the black African south has left millions dead.