KOTA KINABALU (THE STAR/ASIA NEWS NETWORK) - An Abu Sayyaf sub-commander high on the Philippines' wanted list was among three gunmen killed in a gunfight at a plantation in the east coast of Sabah, regional intelligence sources told The Star.

They said Nurhassan Jamiri was armed with a high-powered rifle when he was gunned down.

He had been off the radar for nearly seven years.

Nurhassan, from Basilan island in southern Philippines, is suspected to have been involved in the 2011 Makati IED (improvised explosive device) attack on a bus in Manila that killed five passengers.

He was also the captor of Warren Rodwell, a 54-year-old Australian who was held by the Abu Sayyaf for 472 days in Basilan in 2011.

In his hometown of Basilan, Nurhassan led a notorious Abu Sayyaf sub-group that included his cousin Mussana Jamiri, a bomb expert who died in 2016 when the improvised bomb he was carrying accidentally exploded as he was trying to escape from government forces.

Intelligence sources believe that Nurhassan was involved in the Marawi City siege last year (2017) and might have fled to Sabah to seek refuge about three months ago.

At a news conference in Tawau on Wednesday (Feb 28), Eastern Sabah Security Command (Esscom) commander Datuk Hazani Ghazali said the gunmen killed in a shootout at the Tawau plantation on Tuesday are suspected to be linked to a cross-border terrorist network that might be planning an attack on Sabah.

He said they could also be linked to 10 people arrested recently by the Bukit Aman anti-terrorism unit for planning to carry out attacks in the state.

Hazani said that while police had yet to positively identify the three gunmen, the weapons recovered - including a Colt M4 rifle and a revolver - did not look like those used by an armed robbery group.

Police also recovered a .38 revolver with six bullets, a bag containing nine bullets, two packets of drugs and also a Perodua Kancil car that had been stolen from Kota Kinabalu.

"We are taking their photos and fingerprints to identify the three," said Hazani.

He said Tawau district police chief Asst Comm Fadil Marcus had also noted that the trio seemed to operate in a tactical manner before they were shot dead.

"We are still trying to study their motives and which group they belonged to. They could be part of the Islamic State or other organised groups," said Hazani.

However, he did not want to speculate if they were Abu Sayyaf militants who took part in the Marawi siege.

Hazani said authorities were working with their counterparts in the Philippines to help identify the three, who had no documents when they were shot dead. He said the trio were not on Esscom's most-wanted list.

The trio had opened fire at a pursuing police party inside a plantation about a kilometre from the main Kalabakan-Keningau road in a four-minute shootout that ended with the death of the three at about 3.20pm on Tuesday.