Darfur's most-wanted rebel leader vowed on Monday to keep up his offensive, saying he can exhaust Sudan's military by fighting it across Africa's largest nation.
In a telephone interview, Khalil Ibrahim explained his military success so far by saying, "We are more spread out and we move fast."
The speed of his forces was widely credited with allowing Ibrahim's men to reach the outskirts of Khartoum to launch an attack on Saturday. They set out from the Darfur and Kordofan regions under cover of night in pickup trucks and, Ibrahim said, vehicles similar to those used by the army.
They were spotted by the military but outran pursuers as they raced across the vast arid terrain of central Sudan with little obstruction.
Ibrahim spoke while saying he was on the run in the capital Khartoum's twin city of Omdurman, where his Justice and Equality Movement (JEM) launched a daring raid on Saturday. It is the closest Darfur's rebels have ever gotten to the seat of the government.
"I am still in Omdurman. I am not safe, but I am with all my forces," said Ibrahim, countering government claims that the assault was quashed. He said reinforcements were on their way.
Gunfire could still be heard in Khartoum on Monday morning.
The attack, which Khartoum said it repelled, has shocked the government, which is conducting a fullscale manhunt for Ibrahim and cracking down on other opposition figures. Islamist opposition politician Hassan al-Turabi, accused of links to JEM, was detained and questioned on Monday, before being released uncharged.
JEM has emerged as the most effective rebel movement in Darfur, where ethnic Africans took up arms against the government in 2003 to protest discrimination.
Ibrahim declined to explain how his forces managed to attack a city hundreds of kilometers from their bases in Darfur, but he hinted at allies inside Khartoum itself.
JEM, unlike other movements in Darfur, has also succeeded in expanding its operations out of Sudan's wartorn western region into the central province of Kordofan, next to the capital.
Ibrahim's close family ties with the powerful Chad-based Zaghwa tribe has bolstered his ranks and military capabilities, especially as relations have declined between Sudan and its western neighbor.
Sudanese President Omar al-Bashir has accused Chad of being behind the attack and reserved Sudan's right to retaliate, while his top adviser Nafie Ali Nafie said Ibrahim was just fooling himself.
"Those who dream of taking over Omdurman are delusional and don't know the people of Sudan," he was quoted by the official news agency as saying on Sunday.
Sudanese television, also reported that Ibrahim had asked Chad to send a helicopter to evacuate him.
Chad, meanwhile, has closed its border with Sudan "to avoid any infiltration and suspicious movement," said Communication Minister Mahamat Hissene late on Monday.
The more than 1,000km long border between the two countries runs through some of the most inhospitable and remote countryside in the world and armed groups have long passed through it with impunity.
Experts say Ibrahim's advance toward Khartoum was aimed at bringing the Darfur conflict home to the heart of the regime's powerbase and force it to confront the crisis, which has claimed 200,000 lives and displaced 2.5 million people.