The president of South Sudan says attacks by rival Sudan amount to a declaration of war on his country.

Salva Kiir made the remark Tuesday during talks with Chinese President Hu Jintao in Beijing. Kiir arrived Monday for a five-day visit.

On Monday, Sudanese warplanes bombed a market and an oil field in South Sudan, killing at least two people after Sudanese ground forces reportedly crossed into South Sudan with tanks and artillery.

Sudanese President Omar al-Bashir has vowed to press ahead with his military campaign until all southern troops or affiliated forces are chased out of the north.