A Hezbollah commander has been killed on "jihad duty" in Iraq, the group's TV channel has said, indicating the Lebanese group that is already fighting in Syria's civil war may be involved in a second front in the region.

Sources in Lebanon told the Reuters news agency on Thursday that the Hezbollah commander Ibrahim al-Hajj was killed in a battle in Tal Afar near Mosul, a city in northern Iraq seized last month by the Islamic State group.

Hajj, described as a technical trainer, was buried in the village of Qilya in the Bekaa Valley on Wednesday, a Hezbollah official told Al Jazeera's Beirut bureau. Pictures and videos posted on social media showed the funeral procession.

Hezbollah's Al-Manar TV referred to Hajj as "commander", saying he died while "performing his jihadi duties".

Ibrahim al-Hajj

Al Jazeera's Beirut desk said that Hajj's coffin was accompanied by another when it arrived at Beirut international airport on Tuesday. The identity of the other body is unknown.

In July 2006, Hajj was part of a group of Hezbollah fighters who crossed into Israel, captured two Israeli soldiers and brought them into Lebanon, Lebanese security officials told the AP news agency.

Hezbollah, an Iranian-backed Shia group, had previously said that its advisers were offering guidance to Shia fighters in the Iraq conflict, which escalated last month when the Islamic State group seized swaths of territory from the Shia-led government in Baghdad.

A Hezbollah commander who had fought in border areas with Syria told the National newspaper in United Arab Emirates that his brother-in-law was one of those sent last month to Baghdad and Samarra to monitor the Islamic State’s movements.

"We have had a presence there for a long time, of course, but it’s increasing for obvious reasons," said the commander.

Hezbollah's deployment in Syria has helped President Bashar al-Assad's government strengthen its hold on power by re-establishing control over a strategic corridor of territory stretching north from Damascus.

The group says it is fighting in Syria against the threat posed by Sunni rebels.

Assad is an ally of Iran and a member of the Alawite offshoot of the Shia sect. Tehran also has longstanding ties to Shia politicians in Iraq.

Hezbollah was founded with Iranian help in the early 1980s and fought to drive out Israeli forces that occupied southern Lebanon until 2000.

Source: Al Jazeera and agencies