Image copyright AFP Image caption Security forces have been battling the bandits for days

Pakistani troops have been using helicopter gunships to try to dislodge a group of bandits from their hideouts in Punjab province. The offensive comes after more than 20 police officers were taken hostage by the gang.

Who are the Chhotu gang?

They are a gang of bandits operating along a stretch of Indus river in the remote south of Punjab province. Led by Ghulam Rasool, nicknamed Chhotu, they have been active in the region for more than a decade. The gang's members run into hundreds - more than 300 according to one account. It is one of the more prominent gangs among dozens operating along a 150km (95 mile) stretch between Dera Ghazi Khan in Punjab and Kashmore in neighbouring Sindh province. These gangs are linked and conduct a range of activities including smuggling, gun-running, kidnapping for ransom and highway robberies.

Image copyright ISPR Image caption Chhotu and his supporters are reported to be well armed

Where do the gang live?

Chhotu and the rest of the core of the gang come from a branch of the Mazari tribe which dominates the Rojhan sub-district of Rajanpur. Remote and poor, the area is marked by feuds over land and family honour. It is dominated by politically influential landowners who are accused of paying off both the police and the bandits to protect their own interests.

The Chhotu gang controls some key river islands along Rajanpur district, which are deeply forested. These islands lie between the Punjab regions of Rajanpur and Rahimyarkhan, and Kashmore district in Sindh. This riverine belt lies at the confluence of southern Punjab, Balochistan, Sindh, Khyber Pakhtunkhwa and the Federally Administered Tribal Areas. It has served as a hideout of choice for bandits and freedom fighters/militants since the colonial era because it provides easy access into different jurisdictional zones that often lack a co-ordinated response.

Why did troops go on the offensive?

Due to the remoteness of the region, banditry has traditionally attracted little attention. Besides, the Mazari tribal leaders have often been able to prevail on the bandits to reverse actions that might embarrass the government. So in 2005, the Chhotu gang found themselves under considerable pressure after they kidnapped 12 Chinese engineers from nearby Indus Highway. They ended up releasing them without a ransom.

Image copyright AFP Image caption More than 1,500 security personnel have been battling the gang

Many believe the army's current move against the bandits is part of its plans to reassure the Chinese and secure the Indus Highway, which passes through the area and is the main route for the $46bn (£32bn) economic corridor the Chinese propose to build to connect north-western China with the Pakistani port of Gwadar.

The area is also understood to have served as a sanctuary for sectarian militants and Baloch insurgents, with whom the bandits are believed to share economic interests. In a recent telephone interview with Zafar Aheer, a Jang newspaper correspondent based in Multan, Chhotu admitted they were using Indian-made weapons, although he added they had been procured from Afghanistan.

Mr Aheer, who met Chhotu in his island hideout in 2006, says the gang members were armed with both light and heavy machine guns, including an anti-aircraft gun which he said was planted near one of Chhotu's camps.

How badly have the bandits been hit?

During 18 days of police action, the bandits killed seven policemen and took 24 of them hostage. They have lost two men in the fighting so far.

Since the army arrived on the scene there have been reports of shelling of the bandits' hideouts, but no ground action has been reported yet.

One reason may be because the Chhotu gang are using hostages as human shields.

Civilian populations along the riverbank, which may get caught in crossfire, have also not fully vacated the area yet despite several warnings

Who is Chhotu?

The word Chhotu is a pet version of Chhota, meaning a small boy, and was given to him by Baba Lowng, the leader of a gang he joined when he was barely in his teens. His story is typical of any tribal youth from this region.

The son of a small farmer, he served as a table boy at a truckers' tea stall in Kashmore in 1988, when he was 13. He told his Jang interviewer that one of his brothers went to jail because of a tribal dispute, and his father and other brothers went on the run to avoid arrest. A year or so later, he himself was implicated by some policemen in a "false" theft case after he failed to pay them bribes.

In their absence, their family land, some 12 acres in all, was appropriated by their neighbours.

When he came out of jail two years later, he joined Baba Lowng's gang to retrieve his family land. Later his brother also joined him.