MOUNTED ON HIS bike, wearing a T-shirt emblazoned with a corporate logo, Kyaw Soe resembles one of the myriad food-couriers zipping through Yangon, Myanmar’s biggest city. But his bag contains no food. It is a convenient disguise for somebody whose mission requires him to rove the city, looking not for door numbers but for hidey-holes in which to plant explosives.

Mr Kyaw Soe (not his real name) belongs to a covert group of people trying to destabilise Myanmar’s military junta by blowing up the homes and offices of those who work for the regime. Before the army launched its coup four months ago, ending a ten-year experiment with democracy and returning the country to military rule, Mr Kyaw Soe “had never dared to pick up a gun.” In February and March, he, like hundreds of thousands of Burmese, took to the streets to engage in peaceful protest against the putsch.

But the army’s brutal crackdown, in which more than 850 people have died and more than 6,000 others have been arrested, has pushed many who oppose the coup to change strategy and tactics. The resistance no longer wishes merely to reverse the coup, but to tame the army, which has ruled the country for most of the past 60 years. Deposed parliamentarians have formed a shadow government, and ordinary citizens like Mr Kyaw Soe have taken up arms. In cities, underground operatives are assassinating officials from the military government. In the countryside, newly formed militias are attacking army units. Even before the birth of this “revolutionary movement”, as Thant Myint-U, a Burmese historian, calls it, Myanmar was racked by ethnically based insurgencies (see map). Since the coup, several of these ethnic militias have launched offensives against the Tatmadaw, as the army is known. The proliferation of armed uprisings poses the most serious challenge to the army’s hegemony in a generation.

The most battle-hardened of the forces arrayed against the Tatmadaw are the ethnic militias. Two of the oldest and biggest rebel groups, the Kachin Independence Army (KIA) and the Karen National Liberation Army (KNLA), launched offensives in March, seizing army bases and police posts across Kachin and Karen states. A “meat-grinder” battle near the Chinese border that has gone on for months “has seen some of the heaviest fighting ever between the KIA and the Tatmadaw,” says Anthony Davis, a security analyst, with almost an entire army battalion reportedly wiped out in just two days in April.

The Tatmadaw is even losing skirmishes against less experienced rebels armed with home-made hunting rifles. On May 31st the Karenni Nationalities Defence Force (KNDF), a merger of established insurgent groups and new militias from Kayah state, ambushed 150 soldiers. In retaliation, the army deployed helicopters, fighter jets and heavy artillery. Though the KNDF’s claim to have killed 80 soldiers is likely to be an exaggeration, says Mr Davis, the scale of the retaliation suggests the Tatmadaw suffered humiliating losses. He suspects that experienced troops have probably been deployed to fend off the KIA and KNLA, leaving less capable troops to tackle new outfits like the KNDF, who know the terrain better and are more motivated. “We are defending our land,” says Thomas, the KNDF’s information officer (who goes by one name). “The regime’s forces were just following orders.”

Unusually, the Tatmadaw must also contend with fury among Bamars, the majority ethnic group, who are clustered in the centre of the country. Thousands of urban activists have received basic military training in the redoubts of ethnic militias in the jungle and have, like Mr Kyaw Soe, returned to the cities to put their new skills into practice. More than 300 bombs have exploded in police stations, state-owned banks and government offices since February, according to Radio Free Asia, a news website. The junta claims that more than 300 “innocents” have been killed in bombings and shootings since the coup, though RFA can confirm only 12 assassinations. At the same time, in rural areas, scores of new militias that have declared allegiance to the shadow government have attacked police stations, clashed with soldiers and ambushed military convoys.

There are signs of co-ordination between ethnic rebels and Bamar fighters. In late April Chinese-made rockets were launched at two air-force bases in central Myanmar. These weapons were almost certainly obtained from the KIA or KNLA, says Mr Davis, but neither group could have deployed and fired the projectiles in central Myanmar without help from local Bamars. It is the first time that military targets in the centre of the country have been attacked with heavy weaponry.

The Tatmadaw is taking a pounding. Mr Davis estimates that the security forces have suffered 500 fatalities since the coup. The creation in May of an auxiliary militia to patrol big cities and towns shows how overstretched it is. Even Min Aung Hlaing, the commander-in-chief, admitted, in an interview with a broadcaster from Hong Kong in May, that the situation is not “100% under control”.

Yet the Tatmadaw is far from being defeated. Even were its opponents to band together, as the shadow government hopes, its 350,000-odd soldiers would still dwarf the rebels’ combined forces of around 80,000. Over the past decade it has built up an arsenal of sophisticated weaponry, enabling it to mount combined land and air offensives. A resolution passed on June 18th by the UN General Assembly, calling for an end to arms sales to Myanmar, as well as an end to violence and the release of detainees, will make little difference. The Tatmadaw’s two biggest suppliers, China and Russia, abstained.

There have been hundreds of defections from the army since the coup, but it is very unlikely that enough would abandon the force to influence the conflict’s outcome. Plus, their fortunes may change with the weather. Hostilities with ethnic rebels, who live in the country’s uplands, are usually suspended when the monsoon arrives. If that annual pattern holds this year, the Tatmadaw may be able to redeploy troops to the heartland, Mr Davis predicts.

The shadow administration, known as the National Unity Government (NUG), is trying to knit the disparate anti-regime forces into a standing army. But different ethnic rebels are wary of one another—past efforts at co-operation have failed—and of the NUG, which was formed by a Bamar political party criticised before the coup for ignoring the grievances of ethnic minorities. Even the Chin National Front, the only ethnic militia formally allied with the NUG, is worried that Bamars will dominate their coalition, says Salai Lian Hmung Sakhong, who is the front’s vice-chairman and the NUG’s minister of federal affairs. Some rebel groups have no interest in taking on the Tatmadaw. They include the biggest, the United Wa State Army, with 30,000 troops. Others, such as the Arakan Army, which had engaged the Tatmadaw in fierce fighting until last November, see an opportunity to extract concessions from the army while it is under pressure.

“It is highly unlikely that the shadow government will ever have full centralised control over all the various new militias formed to stop the coup, let alone the ethnic-armed organisations who will remain allies at best,” says Kim Jolliffe, an analyst. But the fragmented nature of the resistance also makes it more difficult for the Tatmadaw to root out insurgents. And Mr Lian Hmung Sakhong points out that the Tatmadaw’s brutality has turned the entire country against it. For the first time since some students took up arms after the bloody suppression of an uprising in 1988, Bamars are joining ethnic rebels in their war against the army. Resistance fighters may be outgunned by the Tatmadaw, but Mr Lian Hmung Sakhong, speaking of the junta’s leader, says, “Min Aung Hlaing cannot kill the whole people, the entire country.”