Beirut, Lebanon - Lebanese security forces and soldiers have been searching for the perpetrators of a mass shooting that left nine people, including two children, dead in the mountain town of Baakline.

Two children, one woman and six men - five of whom were Syrian and four Lebanese - were killed in the attack on Tuesday, believed to be the worst non-conflict shootings in at least two decades.

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The state-run National News Agency (NNA) reported late on Tuesday that two brothers, identified as MH and FH, are suspected of being behind the multiple murders. The NNA said the motive was "revenge" against a Syrian man, though further details were not provided.

The NNA said MH first killed his Lebanese wife before going on to kill four Syrians. The wife's brother then went to calm him down, and MH killed him too.

The suspect then headed through an agricultural area with his brother where he encountered two Lebanese men ploughing a field. The NNA reported that both were killed.

The two brothers then encountered a Syrian man, and MH shot and killed him too.

They then drove their car to near Baakline's secondary school, parked it, and escaped to an unknown area, the NNA said, adding that 20 square kilometres (7.7 square miles) had been searched overnight in an area with rugged terrain.

'No issues' between Lebanese and Syrians

The crime occurred in a remote part of the town near a wooded area where Syrian labourers have lived for more than 10 years, according to Baakline Mayor Abdullah al-Ghussaini.

He told local media at the crime scene there had been "no issues" between locals and Syrians, and said the municipality would provide land for them to be buried.

Hundreds of thousands of Syrian labourers have long come to Lebanon for seasonal work, with many living in the country since the outbreak of the Syrian war nine years ago.

About 900,000 Syrian refugees are registered with the United Nations High Commissioner for Refugees in Lebanon, though officials estimate that closer to 1.5 million actually live in the country.

Tensions between some host communities and Syrian refugees have increased over the past year as the economic situation in the country deteriorates, with some parties laying part of the blame for the crisis on the large refugee presence.

Tuesday's mass shooting was facilitated by widespread weapon ownership in Lebanon, with many guns left over from the country's 15-year civil war that ended in 1990.

However, non-conflict mass shootings are not common.

In March 2019, an off-duty soldier shot four migrant workers in the Bekaa Valley town of Zahle, killing one.

In 2017, a 14-year-old boy killed four people with a pump-action shotgun during a rampage in the capital, Beirut.

In 2002, an employee at Lebanon's education ministry opened fire on his colleagues, killing eight people.