NAIROBI, Kenya — Sudan is bombing oil-rich regions of South Sudan in order to scare away American and Chinese investors, a South Sudan official said Monday, as U.S. President Barack Obama expressed concern about the growing tensions between the two countries.

South Sudan government spokesman Barnaba Marial Benjamin said Sudan is bombarding disputed areas in South Sudan despite a Feb. 10 nonaggression and cooperation pact signed by both countries in African Union-led negotiations in Ethiopia.

“As we speak today they are continuing bombing villages,” Benjamin said.

Sudan described as “false and unfounded” claims by South Sudan that Khartoum was attacking and occupying southern Sudan territories.

A statement issued by Sudan’s government delegation to the talks to resolve disputes between the two countries in Addis Ababa, Ethiopia, instead accused South Sudan of attacking a region in Sudan.