An ISIS militant who appeared in a video beheading a foreigner in 2016 has been killed in a battle with U.S.-backed forces in Syria.

Indonesian citizen Muhammad Saifuddin, who used the aliases Abu Walid and Mohammed Karim Yusop Faiz, was confirmed dead by national police and a family member yesterday.

He was killed on January 29 in eastern Deir Ezzor province where an international coalition is trying to defeat remaining pockets of ISIS extremists.

ISIS executioner Muhammad Saifuddin (far left), who appeared in a video beheading a hostage, has been killed by tank shell in Syria

Indonesian National police spokesman Dedi Prasetyo said Saifuddin was killed by shrapnel from a Syrian forces tank in the battle.

Saifuddin's older brother, Muinudinillah Basri, said the family learned about the death through an instant messaging app.

'There was a photo of his body and I can recognize it,' he said.

Saifuddin, 40, was a recruiter for ISIS and appeared in several videos on radical websites.

They included a 2016 video that showed him along with two other Southeast Asian militants killing three prisoners who were dressed in orange jumpsuits and forced to kneel before being slain.

The terrorist's older brother said the family learned about Saifuddin's death on January 29 through an gruesome instant messaging app picture

In August the U.S. designated Saifuddin and the two others - Malaysian Mohammad Rafi Udin and Filipino Mohammed Reza Lahaman Kiram - as global terrorists.

Basri said the family hadn't heard from Saifuddin since he left Indonesia to join IS in Syria with his wife and children about four years ago.

They believed was originally radicalized by a Christian-Muslim conflict in Indonesia's Ambon region from 1999 to 2001 along with his twin brother, who died in the fighting.

One of Saifuddin's Indonesian friends, convicted militant Sofyan Tsauri, said that in radical circles Saifuddin was thought to be trusted by ISIS leader Abu Bakr al-Baghdadi as a leader of Southeast Asian Islamic militants.

Tsauri, a former member of the al-Qaida-affiliated network responsible for the 2002 Bali bombings who now collaborates with Indonesia's counterterrorism agency, said Saifuddin fled to the southern Philippines shortly after the Bali bombings with two other senior Indonesian militants.

He was arrested in the Philippines while attempting to return to Indonesia with weapons and explosives and sentenced to nine years in prison in 2007.

After marrying the widow of an Indonesian suicide bomber following his early release in 2013, Saifuddin sank below the radar of authorities but reappeared several years later in an ISIS propaganda video that urged Indonesian Muslims to oppose the government and join violent jihad in Syria or the southern Philippines.

Saifuddin was a senior member of ISIS who was perceived to be a leader among Southeast Asian militants and trusted by the terror group's leader Abu Bakr al-Baghdadi

'Since long ago he had aspired to go international,' Tsauri said. 'He had a convincing track record that gained trust and an important position in ISIS.'

In a news conference on Monday, Police spokesman Prasetyo said early last month an Indonesian militant, Harry Kuncoro, was arrested at Jakarta's international airport. He had planned to travel to Syria via Iran with Saifuddin's help.

Prasetyo said Kuncoro, who was sentenced to nine years in prison in 2012 for harboring Bali bomber Umar Patek and illegally possessing weapons, used the Telegram instant messaging app to communicate with Saifuddin after being paroled last year.

Saifuddin sent Kuncoro $2,100 for traveling to Syria, advised him to travel via Iran's Khorasan province and gave him contact numbers for Indonesian militants living in Khorasan, Prasetyo said. He had obtained a passport using a fake national identity card.

This week the Kurdish-led Syrian Democratic Forces (SDF), backed by artillery fire from a U.S.-backed coalition, are battling to force ISIS out of their last holdout in the eastern city of Baghouz in a final push.

Up to 600 jihadists as well as hundreds of civilians are believed to remain inside the ISIS patch.

Tens of thousands of people, mostly women and children related to ISIS fighters, have fled the shrinking jihadist holdout to opposition territory, many of them claiming they were not supporters of the terror group.

On Monday the U.S.-backed coalition maintained a steady beat of bombings on the area as the Syrian fighters battled a fierce jihadist counteroffensive.

The UK-based Syrian Observatory for Human Rights said 12 SDF fighters and 19 jihadists were killed in the fighting on Monday.

U.S. President Donald Trump said that the coalition may declare victory over IS in the region in the coming days.

The alliance has been battling to oust the jihadists from the eastern province of Deir Ezzor since September.