JUBA, South Sudan (AP) — Sudan’s military bombed an oil field in South Sudan today, a South Sudan official said, as a dangerous flare-up in border violence appeared to scuttle plans for a presidential summit between the two countries.

Unity State Minister of Information Gideon Gatpan said Sudan dropped at least three bombs near oil fields in the town of Bentiu. Gatpan said the extent of any damage wasn’t immediately known.

The attack comes one day after Sudan and South Sudan clashed in the disputed border town of Jau, prompting Sudan to cancel President Omar al-Bashir’s trip to meet with South Sudan President Salva Kiir next week.

South Sudan broke away from Sudan last year, but tensions between the longtime foes have remained high.

Among the unresolved issues is the demarcation of the border and an agreement to share oil revenue. South Sudan earlier this year stopped pumping oil because it said Sudan — which owns the pipelines the south’s oil must travel through — was stealing its oil.

Despite the increased violence, South Sudan held out hope the presidential meeting could still happen. South Sudan Minister of Information Barnaba Benjamin Marial said the south still expects al-Bashir to attend the meeting next week, saying South Sudan had not received an official cancellation from Khartoum.

Marial said the south believes that “forces of war” in Khartoum were trying to derail the peace process, but not al-Bashir himself. He said the south would not take the bait.

“ Our president has said clearly we will not be dragged into a senseless war,” Marial said. “We will not be dragged into a conflict with Sudan.”

The two countries disputed which side was the aggressor in Monday’s clash in Jau.