Lawyers for a Sudanese Christian woman in hiding at the U.S. embassy in Khartoum sought the dismissal on Sunday of forgery charges against her so she can leave the country.

"We submitted our request" to prosecutors, Mohanad Mustafa, a lawyer for Meriam Yahia Ibrahim Ishag, 26, told Agence France Presse.

A Darfur rebel leader, who experts said was responsible for some of the deadliest attacks against Sudanese forces, has been killed in action, state-linked media said on Sunday.

North Darfur state governor Osman Kbir announced the death of Ali Karbino on Saturday, said the Sudanese Media Center (SMC) which is close to the security apparatus.

Rebels in Sudan's war-torn South Kordofan region shelled the state capital Saturday during what they called a counter-attack on an area the government said it had seized in early June.

A resident of the town confirmed the shelling, saying rounds had passed over his house.

A quarter-century after it took power in an Islamist-backed coup promising "salvation" for Sudan, critics say Field Marshal Omar al-Bashir's regime has instead destroyed it.

Bashir, 70, is accused of war crimes in the Darfur region and has maintained power despite internal divisions within his ruling National Congress Party (NCP).

Egyptian President Abdel Fattah al-Sisi landed in Islamist neighbor Sudan on Friday for what an analyst said would be an attempt to shore up a regional alliance against Islamic "terrorism".

An AFP photographer at Khartoum airport confirmed the Egyptian leader's plane had touched down.

The husband of a Sudanese Christian woman facing threats after her apostasy death sentence was overturned expressed relief on Friday that the family has been given refuge at the U.S. embassy.

"Really, it's good," Daniel Wani, the American husband of Meriam Yahia Ibrahim Ishag, 26, told AFP by telephone, adding that embassy staff have been "very helpful and very nice."

A Sudanese Christian woman who faces death threats after a court cleared her of apostasy has been charged with forgery after trying to leave the country, a lawyer said on Wednesday.

"She is arrested," Mohanad Mustafa told Agence France Presse.

The American husband of a Sudanese Christian woman cleared by a court of apostasy but facing death threats from extremist Muslims said on Wednesday they are fearful and want to leave Sudan.

"We are worried. That's why we want to get out of here as soon as possible," Daniel Wani told Agence France Presse from a Khartoum police station where his wife, Meriam Yahia Ibrahim Ishag, 26, is being questioned.

Intensified bombing in Sudan's war-torn South Kordofan may be part of an attempt to starve the population, Amnesty International said on Wednesday.

The air raids in recent weeks are "unprecedented in their scale and impact," the London-based watchdog said, citing human rights monitors.

A Sudanese Christian woman was arrested Tuesday at Khartoum airport a day after a court annulled her death sentence for apostasy and released her from prison, a source familiar with the incident said.

"The National Security took her and Daniel," said the source, referring to Meriam Yahia Ibrahim Ishag, 26, and her American husband Daniel Wani.