NAIROBI, Kenya — Sudan attacked South Sudan with warplanes and ground troops, only days after Sudan said its military had forced the South’s forces out of a contested oil-rich region, South Sudan said on Monday.
South Sudan said last week that it had withdrawn from the region, known as Heglig, in response to international pressure to stave off all-out war.
But an aerial bombardment and ground assault by Sudanese armed forces on Sunday and Monday that went beyond Heglig and into South Sudan, according to a South Sudanese official, indicated that fighting between the two nations might not be over, echoing statements made by President Omar Hassan al-Bashir of Sudan last week that his nation would drive the “insects” in the South from power.
Mr. Bashir insisted that a military approach to the dispute was necessary, telling troops in Heglig on Monday that there would be no talks with the South Sudanese because they “do not understand anything but the language of the gun and ammunition,” news agencies reported.
A South Sudanese spokesman said Sudan had been bombing South Sudan, including the regional capital of Bentiu — a target of previous air assaults — and that South Sudan had repulsed Sudanese forces on the ground Sunday in the area of Tashwin.
A Sudanese government spokesman denied the attacks in South Sudan as “accusations” but said that Sudan’s army was mobilizing to fight South Sudanese troops that he said were deployed around Heglig and in the rebellious Sudanese regions of the Nuba Mountains and Blue Nile, where Sudan has accused South Sudan of supporting insurgents.
The United States, the United Nations and the African Union all condemned South Sudan for sending troops into Heglig this month and bringing the two countries to the brink of war. South Sudan, which calls the area Pantho, said it considered the area part of the South.
Then on Monday, Sudan came under blistering criticism as well. In a statement, the State Department condemned “Sudan’s military incursion into South Sudan” on Sunday, saying that Sudan “must immediately halt the aerial and artillery bombardment in South Sudan.”
But the Sudanese government spokesman, Rabie A. Atti, said fighting between the two militaries was not over. “We should have never given up the region of South Sudan,” Mr. Atti said.
South Sudan became an independent nation last year, the culmination of a 2005 peace accord that ended decades of fighting between the two sides. In 2009, the Permanent Court of Arbitration, an international organization, ruled that Heglig was outside the borders of the contested area of Abyei, which lies between Sudan and South Sudan, and therefore belonged to the government in Khartoum.
“Since yesterday and today, they have been bombing,” the South Sudanese information minister, Barnaba Benjamin Marial, said Monday. “There has also been a ground attack on our positions and we have the right to react.”
Mr. Marial said that causalities had been reported but that a figure could not yet be confirmed. News agencies reported one to three deaths as a result of the air attacks.
Sudan and South Sudan have been at loggerheads over how to share oil — largely found in South Sudanese territory but pumped north through Sudan for export — since South Sudan broke away from Sudan last year. Then this month, tensions exploded when South Sudan captured Heglig from Sudan.
Mr. Marial said Monday that South Sudan had completely withdrawn from Heglig and that the withdrawal was voluntary, but news reports along the border region suggested that Sudan’s bombardment may have forced South Sudan from the area.
On Monday, a satellite-imagery monitoring project published images that it claimed shows Sudanese jet fighters perched along the Sudan-South Sudan border, as well as evidence of looting by South Sudanese. It also said it showed evidence of the destruction of oil facilities in Heglig, which are essential to oil revenues for Sudan.
In a fiery speech last week, President Bashir claimed victory over South Sudan in Heglig. In earlier speeches, Mr. Bashir spoke of “occupying” the South Sudanese capital of Juba and seeking to topple the South Sudanese government.
Mr. Bashir also said Sudan would not allow South Sudan to use Sudan’s oil pipelines to export oil.