Earth-shattering thunder over the jungle canopy made it difficult to distinguish the storm from incoming mortar rounds as 80 ethnic Karen rebels were trying to fend off about 400 attacking Myanmese soldiers last Tuesday. Pounding the Karen lines with artillery, machine-guns, rocket-propelled grenades and automatic rifles, junta soldiers aimed to take the high ground on the mountain where the rebels were dug in with fewer men and less powerful weapons - but with the distinct advantage of firing down on the Myanmese ascending the heavily mined mountainside. After a fierce battle that lasted about 30 minutes and brought the closest attackers within 100 metres of rebel positions, the junta soldiers ceased fire and retreated - leaving four of their soldiers dead according to radio transmissions intercepted by rebels later that day. The defenders of the Karen National Liberation Army (KNLA) held off the initial assault without taking casualties, though they were wet, cold and tired - and without eliminating the threat of the 400 Myanmese soldiers still within striking distance of their jungle trenches. Two days later, the Karen guerillas tactically retreated into the surrounding jungle and the soldiers took over their 7th brigade headquarters at Ta Kaw Bee Tah in Myanmar's Myawaddy township. Last week's fighting was the latest in a decades-long war between Yangon and the Karen, who are fighting for an independent homeland in eastern Myanmar - one of the longest unresolved conflicts in the world waged by one of the largest ethnic groups in Southeast Asia without an independent state. Numbering about seven million, the Karen inhabit the mountainous jungles that straddle the border of eastern Myanmar and western Thailand. When Myanmar, formerly known as Burma, received independence from Britain in 1948, the Karen demanded an independent state of their own - as promised to them by the British during the second world war, when Karen fighters sided with them during the campaign for Burma. In 1949, the Karen took up arms for their independence drive and have been fighting ever since. The capture of the KNLA's 7th brigade headquarters was the main objective of a junta offensive that began on August 5, according to KNLA Colonel Saw Ner Dah Mya. But he says the capture was not a setback as his men had just tactically retreated and will 'continue to harass the Burmese with guerilla fighting'. 'Our objective is to hurt them as much as possible,' the colonel says. The KNLA has seven brigades, totalling about 5,000 fighters. Two days before Tuesday's battle, 11 Myanmar army porters reached KNLA positions after escaping and walking through the mine-infested jungle for four days. They were all taken from jails in Myanmar and forced to carry ammunition and supplies for the army. One of the escapees, 46-year-old Zaw Win, says he was forced to carry 2,000 rounds of ammunition weighing about 25kg for more than one month. He was taken from a prison in Pegu Division where he was jailed for involvement in an underground lottery. He says about 1,000 forced porters - mainly prisoners - are being used for this offensive, which includes 10 battalions of government troops, according to Colonel Ner Dah. 'All the porters are afraid,' Win says. 'They want to run away but they are afraid of landmines and they don't know the way.' The 11 escaped porters add that at times they were used as 'human minesweepers' - walking in front of the soldiers in places suspected of being mined - a practice that has been reported in the past by various human-rights groups such as Amnesty International and Human Rights Watch. Win says when the porters were walking with Myanmese soldiers they had to keep pace or they were punished. 'You cannot rest. If you do they will kick you or hit you with a stick,' he says. The escapees are all underweight and say they were only fed once a day for more than a month and then nothing during their four-day ordeal to rebel lines - where they said they were being treated well. Many of them, such as 26-year-old Thang Saw, have badly cut shoulders from rope burn caused by carrying supplies on their backs in bamboo baskets. Saw was also taken from a prison in Pegu Division where he was jailed for knife-fighting. Asked what he thinks about the soldiers for whom he was forced to porter, he replies: 'They are very, very cruel.' Win says the porters were told by their captors that if they escaped and managed to reach KNLA positions, the rebels would kill them. But he says it wasn't the rebels he was afraid of, so he took his chances and fled his unit on the morning of October 8 with another porter, 45-year-old Aung Min. Their captors were wrong. 'I'm just afraid of the SPDC,' Win says, referring to the acronym of the State Peace and Development Council, the official name of Myanmar's ruling junta. With 11 fewer porters and an unknown number of soldiers dead and wounded (the government does not release casualty figures and the junta has remained silent on the latest fighting), the Myanmar Army has accomplished its objective of capturing the KNLA's 7th brigade headquarters. But with 80 Karen guerillas looming in the nearby jungle and reinforcements being sent to the area, keeping it may prove difficult.