New satellite images suggest that the Sudanese government is expanding its military presence in the southern region of Sudan near the border with South Sudan.

The watchdog group Satellite Sentinel Project in partnership with the Harvard Humanitarian Initiative, says that the images demonstrate that the Sudan Armed Forces are “rapidly working to enhance air strike and air assault capacity in two airbases recently captured from rebels in Sudan’s Blue Nile border area.”

These new images, released Friday, come after the Sudan Armed Forces bombed the town of Yida in South Sudan on Thursday in addition to another bombing near the South Sudan border earlier in the week.

Yida hosts more than 20,000 refugees who have fled from the ongoing conflict in the southern region of Sudan where rebel forces and the Sudan Armed forces have been fighting since June.

The White House condemned Thursday’s bombing in a statement, calling the bombing an “outrageous act” and saying “those responsible must be held accountable for their actions.”

“The United States demands the Government of Sudan halt aerial bombardments immediately,” the White House statement goes on to state. “We urge the Government of South Sudan to exercise restraint in responding to this provocation to prevent further escalation of hostilities.”

A spokesman for the Sudan Armed Forces denies that the Sudan has bombed anywhere in South Sudan.

“South Sudan is a state in the United Nations. We respect international law, and it’s impossible that we would do that,” the spokesman Al-Sawarmi Khalid is quoted as saying to Reuters.

South Sudan obtained independence from Sudan in July, after several years of peace talks and a referendum vote in which the people of South Sudan voted in favor of independence from the Sudanese government based in Khartoum.