Janjalani, who carries a P10-million prize on his head, and his men breached the military cordon after nearly five hours of sporadic fighting in the outskirts of Maitum and Palimbang towns in Sultan Kudarat, Lt. Col. Daniel Lucero, Armed Forces spokesman, said.
Janjalani is believed to be still in the Maitum-Palimbang boundary or in nearby municipalities. Combined military forces are pursuing his group.
The military said Janjalani, reportedly along with two Yemeni nationals, fled the island-province of Basilan in October 2001 and reached Sultan Kudarat in April 2002 after spending some time in Jolo, Sulu.
Lucero said elements of the Armys 7th Special Forces Battalion, under the 601st Infantry Brigade, caught up with the group of Janjalani and Hapilon at about 10:30 a.m. last Monday while they were verifying reports about the bandits presence in Sitio Kadakupan in Barangay Tuanado, Maitum town.
Lucero said Janjalani was not sighted in the encounter site although Hapilons presence there was confirmed.
"But we are not discounting the possibility that Janjalani was, indeed, in the area," he said.
At about 4:30 p.m. the same day, government troops again clashed with Abu Sayyaf rebels in Sitio Makabenban in Barangay Mulun, Palimbang town, about three kilometers from the first encounter site.
A certain Bayan Binago, said to be a member of Abu Sofia, a kidnapping group operating in Central Mindanao, was killed in the clash. There were no casualties on the government side.
Both Janjalani and Hapilon, who carries a P5-million prize on his head, are on the wanted list of the US government for the May 27, 2001 abduction of 21 tourists from a resort in Palawan.
American-Peruvian Guillermo Sobero was beheaded. Fellow American Martin Burnham was killed while soldiers were rescuing him and his wife Gracia in Zamboanga del Norte in July 2002. Gracia was wounded in the firefight.
Early this year, Armed Forces chief Gen. Narciso Abaya said Janjalanis group was being aided by the Jemaah Islamiyah, an Indonesia-based terror network which has links with the al-Qaeda group of international fugitive Osama bin Laden.
The Sultan Kudarat clash occurred as preparations were underway for the joint military exercise of Filipino and American troops in Carmen, North Cotabato on July 26 to Aug. 13.