A Swiss hostage has escaped from Abu Sayyaf extremists after more than two years of jungle captivity in the southern Philippines, officials have said.

Lorenzo Vinciguerra, 49, made his daring escape while government forces were firing artillery rounds near the jungle forest where he was being held in the mountainous Patikul town in Sulu province.

He grabbed a long knife and hacked at an Abu Sayyaf commander before running from the scene, but was shot and wounded by another militant, security officials said.

Philippine army scout rangers later found him and escorted him to safety.

"He was wounded, but he's well and recovering in a hospital," regional military commander Lt Gen Rustico Guerrero said by telephone.

In Bern, the Swiss government expressed relief that Mr Vinciguerra had regained his freedom, but regretted that his Dutch companion, Ewold Horn, remains in captivity.

Mr Vinciguerra thanked the military as he was being treated in hospital.

He said he was happy because he can finally spend Christmas with his family, but worried about his companion, Mr Horn, who is still in Abu Sayyaf custody in Sulu's jungles.

"I talked to him and asked him to join me, but he refused," Mr Vinciguerra said of Mr Horn, adding that the Dutchman had a number of health problems.

Mr Vinciguerra said he felt the extremists would treat Mr Horn well and urged the militants to surrender and start a new life.

And he declared: "My final message to everybody: Put the gun down and come out from the forest. It's a nice life out here."

Mr Vinciguerra was seized by the militants in nearby Tawi Tawi province in February 2012 while on a bird-watching trip with Mr Horn and Ivan Sarenas, a Filipino birdwatcher who served as their guide.

Mr Sarenas, who escaped shortly after they were seized by jumping off a boat that was taking them to Sulu, said he was happy about Mr Vinceguerra's escape, but was saddened that he had been wounded and that Mr Horn was still being held.

He said: "It is not the best news, but it still is good news after so long. I just want to hug Lorenzo for now."

Mr Sarenas said that he was determined to escape, and that Mr Vinciguerra and Mr Horn had agreed to his plan.

Mr Sarenas, a triathlete, said he jumped off the boat and dived deep underwater, fearing that he would be shot on the surface. He managed to swim to freedom and was later rescued by fishermen.

Islamic extremist group Abu Sayyaf was founded in the early 1990s on Basilan island, near Jolo.

It vows to wage jihad, or holy war, in the predominantly Roman Catholic Philippines, but lost its key leaders early in combat, sending it on a violent path of extremism and criminality.

Washington has listed Abu Sayyaf as a terrorist group and blames it for deadly attacks on American troops, foreign missionaries, and tourists and civilians in the south.

The al Qaida-inspired group still has an estimated 400 fighters split into about six factions. The mostly armed rural villagers still hold several hostages, including a Malaysian police officer and a Japanese treasure hunter.

Although weakened by battle setbacks, the militants have survived thanks largely to money collected from ransom kidnappings and extortion.

The Philippine military has recently launched a new offensive against the militants after they staged a new bout of kidnappings, including the seizing of Chinese tourists in neighbouring Malaysia's Sabah state, which is only hours away by speedboat from the southern Philippines.

Marines and army troops assaulted at least three Sulu jungle encampments of the Abu Sayyaf on Saturday, with artillery and gunfire, including in Patikul, killing an unspecified number of militants, according to the military.