Fighting at a Palestinian refugee camp in Lebanon which left at least nine people dead has continued on Monday.

The clashes at the Ein el-Hilweh camp broke out between Palestinian Authority President Mahmoud Abbas' Fatah movement and rival Islamist groups.

Among the dead was a Fatah commander, the movement confirmed.

Established in 1948, the restive Ein el-Hilweh camp is the largest in Lebanon with more than 63,000 registered refugees, the UN says.

Some estimates say the population is higher.

The camp, situated near the southern city of Sidon, falls outside the jurisdiction of the Lebanese security forces.

It is left up to rival factions within the camp to maintain its security, but factional disputes are common.

The weekend's violence erupted on Saturday when a member of an Islamist group was killed, AFP news agency reports quoting an unnamed source inside the camp.

Tensions continued to mount through to Sunday, culminating with the death of the Fatah commander, Ashraf al-Armouchi, and several of his aides.

A ceasefire was agreed late on Sunday, but skirmishes continued through the night.

Automatic weapons and anti-tank fire were heard on Monday morning, according to the AFP news agency.

Dozens of residents have fled their homes within the camp.

Ceasefire negotiations are ongoing, and the local MP is expected to hold a meeting later on Monday to try to resolve the tensions.

In a statement quoted by AFP, Fatah denounced an "abominable and cowardly crime" aimed at undermining the "security and stability" of the Palestinian camps in Lebanon.

The Palestinian presidency denounced the fighting, calling the security of the camps a "red line".

"It is not permissible for anyone to intimidate our people and tamper with their security," it said in a statement.

As well as the nine dead, Lebanese soldiers were also injured during the violence, the Lebanese army said.

The director of the UN agency for Palestinian refugees in Lebanon (UNRWA), Dorothee Kraus, said all the agency's operations in the camp had been suspended.

She called on "all militant parties to ensure civilians' safety and respect inviolability of UN premises".

More than 479,000 refugees are registered with UNRWA in Lebanon, the agency says. About half live in the country's 12 refugee camps, which have "dire" living conditions, it adds.