Al Jazeera reports from south Sudan with a warning that viewers may find some of the images in this report disturbing
Civilians in south Sudan say jets from the north are launching attacks on villages close to the border.
Al Jazeera has obtained exclusive pictures of the village of Jaw after it was allegedly bombed by the Sudanese air force. Among the dead are women and children, Al Jazeera's Haru Mutasa reported from south Sudan.
The violence came on the eve of a visit by Omar al-Bashir, Sudan's president, to China.
Bashir said on Monday that his country's relations with China will not be weakened by Beijing's ties with Southern Sudan.
In remarks made before his four-day visit, Bashir said he was not troubled by Beijing's dual loyalties.
"Our policy, and also China's, stands on the principle that each country is free to adopt the procedures and build relations in the manner that preserves its interests and relations," he told China's official Xinhua news agency.
"Therefore, even if China has established relations with the south Sudan state, that will definitely not be a deduction on its relations with the north."
Declaration of independence
Bashir's visit to China, a major buyer of Sudanese crude oil, comes days before south Sudan is to split from the north and become the world's newest sovereign nation.
Southern Sudan's secession on July 9 is likely to feature in Bashir's talks with Hu Jintao, his Chinese counterpart.
China has been building ties with the emerging state in Southern Sudan but continues to be one of the major supporters of Bashir, who faces indictment from the International Criminal Court over war crimes charges stemming from long-running fighting in the Darfur region.
The south's declaration of independence in July will be the culmination of a 2005 peace deal that ended more than two decades of civil war that killed about two million people.
While south Sudan's independence is expected to take place on schedule, crucial issues remain unresolved.
The areas of debate include: the future of the disputed region of Abyei, which is supposed to be decided in a referendum; the north-south border demarcation; how oil revenues and other resources will be shared; and citizenship.