Militias from rival towns in western Libya battled each other with tanks and artillery on Tuesday in fierce fighting that killed at least 22 people, local officials said.

The clashes erupted over the weekend between the Arab-majority town of Ragdalein and the Berber-dominated town of Zwara, about110 kilometres west of the capital Tripoli. The violence is fuelled by deep-rooted animosity between the neighbours, who took different sides in Libya's civil war that toppled Moammar Gadhafi last year.

The fighting is the latest in a series of local rivalries that threaten to divide Libya along tribal and regional lines. Libya's new leaders, who took power after Gadhafi's capture and killing in October, have struggled to stamp their authority on the country and rein in the myriad armed groups that helped defeat the dictator's forces but have refused to disarm.

In Tuesday's clashes, local Ragdalein official Rami Kaanan said 17 fighters and town residents were killed, including two women and an infant. The infant was killed when a rocket fell on his home, bringing down the ceiling, Kaanan said.

Zwara spokesman Adel Kashbour said five people from his side were killed and 49 wounded.

"The fighting continues. Two rockets landed in the city, killing two young men," Kashbour said of the most recent deaths.

Looting claimed

The clashes began Sunday after fighters from Ragdalein said they took 34 men from the Zwara brigade hostage to avenge what Ragdalein forces said were months of abuses, including the looting. The hostages were released Monday after mediation, but the cease-fire quickly collapsed.

Prime Minister Abdurrahim el-Keib said he, along with his defence minister and chief of staff, met with elders from Zwara on Tuesday and will soon meet with tribal leaders from Ragdalein to discuss a cease-fire and reconciliation.

"We will send forces from the defence and interior ministries to resolve the issue, stop both sides, and be in the middle to quell the violence," el-Keib said. "I am very optimistic."

Libya's Interior Ministry dispatched police forces to the towns on Monday to quell the violence, but were overpowered by the heavily armed local militias. "We have no ability to stop them except through negotiations. We think the Defence Ministry is better equipped for this job because we are equipped with light weapons," Interior Minister Fawzi Abdul-Al said in Tripoli.

Last week, Libyan leader Mustafa Abdul-Jalil acknowledged to The Associated Press that his government has failed to act quickly enough to restore stability. His spokesman, Mohammed al-Hareizi, said Tuesday that security officials in top posts must do more.

"The government must improve its performance and speed up their efforts, or we will have to take extreme measures, especially with the defence and interior ministries, which have failed to deliver any of their plans," al-Hareizi said, warning that ministers could be replaced soon.

Divide-and-rule policies

The conflict between the towns is one of many local rivalries stemming from Gadhafi's 40 years of divide-and-rule policies and Libya's eight-month civil war. Fighting in the remote desert oasis of Sabha between Arab tribes and an anti-Gadhafi African tribe killed around 150 people and left hundreds displaced last week.

Zwara, a town of 45,000 people, is less than 10 kilometres from Ragdalein, which is twice as large. Zwara residents were quick to join the uprising last year that led to Gadhafi's capture and killing in October. The Berber tribe there complained of discrimination under Gadhafi, including neglect and being barred from high-level posts.

Ragdalein, which is inhabited primarily by Arab tribes, was a stronghold for Gadhafi loyalists and heavily armed by his regime during the civil war.

Zwara residents, themselves well armed by rebels during the uprising, accuse Ragdalein's fighters of raping women, looting property and attacking the town last year for opposing Gadhafi's regime. They say they are now being blocked by Ragdalein's tribes from reaching their farms south of the city.