* Military spokesman says parts of Kismayu captured
* Residents say fighting going on outside city
* Loss of Kismayu would bruise, not knock out al Shabaab
* Militants seen resorting to al Qaeda-inspired tactics
By Abdi Sheikh
MOGADISHU, Sept 28 (Reuters) - Kenyan troops attacked the Somali port city of Kismayu on Friday, seeking to drive al Qaeda-linked al Shabaab militants from their last major stronghold and end a five-year rebellion.
The loss of the southern port would deal a huge blow to al Shabaab as it is a lucrative source of revenue and a centre for operations over areas it has controlled in Somalia since 2007, but by nightfall, it was not clear who was in control.
Residents said shelling had subsided after earlier fighting near a beach just outside Kismayu.
No Kenyan forces could be seen in the city centre, where shops and businesses were closed and some preachers called on their followers to join al Shabaab on the frontlines.
"Tension is high. It is getting dark and yet no group controls the town," resident Ali Gelle said by telephone. "People are afraid shells will be fired and there's no hope of getting any food," he said.
Al Shabaab, which formally merged with al Qaeda in February, has been steadily losing its footholds under sustained pressure from African Union peacekeeping forces (AMISOM) and Somali government troops for the past year.
While Kismayu's recapture would go a long way towards stabilising Somalia, which has been largely lawless for the past 20 years, it may embolden the militants to resort to more guerrilla-style attacks.
Kenyan military spokesman Col. Cyrus Oguna said Kenyan soldiers and Somali government troops had advanced on Kismayu from the north, south and from the sea.
"We're moving towards the main city," Oguna told Reuters.
Residents reported fighting near the beach earlier on Friday, about 4 km (2.5 miles) outside the city, as military helicopters hovered overhead.
Many streets were deserted. Some masked men looked on from windows and balconies and the militants appeared to be in control of at least some entrances into the city.
Rukia Jelle, a mother of five, said she could hear "deafening shells" and jets flying overhead.
Residents said Kenyan and Somali troops had advanced to a university campus just to the north of Kismayu and shells had rained down on the presidential palace, an al Shabaab base.
"It's a hilltop palace and no houses surround it. The AU's ships have been shelling in that direction," Gelle said. Oguna could not be immediately reached to confirm that account.
Al Shabaab, which counts foreign al Qaeda-trained fighters among its ranks, is seen as one of the biggest threats to stability in the east and Horn of Africa. It has received advice from al Qaeda's leadership, counter-terrorism experts say.
Western states have poured money into stabilising Somalia for years, unnerved by a rising tide of Islamic militancy.
Those efforts seem to have paid dividends in the past year.
AMISOM has driven the militants out of key urban strongholds, an EU naval force is clamping down on piracy, and a new president was elected in what appeared to be a largely corrupt-free process earlier this month.
There have also been targeted drone strikes against senior militant commanders. Kenya deployed troops inside Somalia last October, blaming the militants for attacks on Kenyan soil.
KISMAYU "NOT A PIECE OF CAKE"
The Kenyan military spokesman predicted an easy takeover.
"For now, we're not everywhere. We've taken a large part of it without resistance," he said.
Al Shabaab, however, said it would not surrender Kismayu.
"Going into Kismayu is not a piece of cake. For us, this is just the beginning, our troops are spread everywhere," Sheikh Abdiasis Abu Musab, al Shabaab's spokesman for military operations, told Reuters on Friday.
Abdirashid Hashi, an analyst with the International Crisis Group said the loss of Kisamyu would be a "huge psychological blow" and a "significant loss" for the militants.
"The die-hard members will continue with their destabilisation strategy of targeted killings, suicide bombings and IEDs (roadside bombs)," Hashi told Reuters, while low-level footsoldiers will see them as "a losing proposition".
He added the loss of funding from local taxes would hurt them less as the group morphed into a guerrilla force.
Al Shabaab's radio station, Radio Andalus, was still airing live in Kismayu, urging residents to take their guns and join the 'jihad', Ismail Suglow, a Kismayu resident, said. The radio also reported al Shabaab fighters had destroyed "enemy vehicles and chased away planes".
"The imam said mujahideen and civilians should go to the frontlines near the beach to fight. Many nodded their heads in affirmation," said Yunis Osman, who attended Friday prayers at Dabaqeyn mosque.
A woman named Halima said some residents who support the militants had already joined them with guns at the frontline.
Hashi said the fighters, who have been in Kismayu for the last five years, would have prepared for an assault they knew was coming after African troops seized Mogadishu, Afmadow, Baidoa, Beledweyne, and Marka.
"I am sure they have some contingency plans and have sent supplies outside the city," he said.
The fallout from Kismayu's eventual capture is far from clear. The city is home to rival clans who will be jockeying for power, especially over control of the port due to lucrative tax revenues.
The U.N. refugee agency said there had been a spike in residents fleeing the city on Thursday. More than 13,000 people have fled Kismayu since the beginning of September after Kenyan forces began targeting al Shabaab's positions in the city.