By Sahra Abdi and Mohamed Ahmed
MOGADISHU (Reuters) - Somali militants linked to al Qaeda prepared to defend a town in southern Somalia on Tuesday from advancing Kenyan and government troops, while a suicide car bomb killed six people in the capital during a visit by a Kenyan minister.
Facing muddy terrain and heavy rains, residents tried to flee Afmadow as the town braced for the next phase of an offensive launched on Sunday by Kenya, along with Somali forces, in a risky bid to secure the border with its anarchic neighbor.
The operation is a major escalation that risks dragging Kenya deeper into Somalia's two-decade-old civil war. But a spate of kidnappings in Kenya by gunmen thought to be linked to al Shabaab led Nairobi to conclude that with its multi-billion dollar tourism industry at stake it had no option but to strike back.
Highlighting the level of anarchy and conflict gripping Somalia, a suicide car bomb exploded near two government ministries in Mogadishu on Tuesday, killing six people, an ambulance worker said, in the second such attack in the capital this month.
A high-level Kenyan delegation was in the city at the time of the blast. In a joint statement Kenya and Somalia agreed they would carry out preemptive strikes on militants that threatened the security of either country.
AFMADOW BRACES FOR ATTACK
Warplanes swooped low over Afmadow, a rebel stronghold which serves as transit point for goods from Kismayu port. A senior commander of a militia group allied to the Western-backed Somali government said his fighters were stationed outside Afmadow as pounding rain slowed the advance.
"We are in the village of Cag Libaax, 12 km (8 miles) to the west of Afmadow. We are heading to Afmadow but we are slowed by rains and muddy soils," said Abdinasir Serar.
Afmadow resident Hussein Osman Roble told Reuters by telephone that most residents had started fleeing toward Dhobley, a border area which Kenyan military sources say has now been cleared of militants.
"Jets have flown low over Afmadow, terrifying the residents, while al Shabaab is digging trenches and tunnels for defense inside and around Afmadow," Roble said.
Meanwhile al Shabaab has assembled columns of fighters and dozens of battle-wagons mounted with heavy machine guns and dug trenches around the town.
Kenyan officials have remained tight-lipped on the details of the operation but a military spokesman said Kenyan troops were 100 km (60 miles) inside Somalia in Qoqani, which is about 30 km (20 miles) to the west of Afmadow.
"It's difficult to estimate the length of our operation," said Major Emmanuel Chirchir.
In a joint communique with the Somali government, Kenyan Foreign Affairs Minister Moses Wetang'ula said the spate of kidnappings was indicative of a change in strategy by al Shabaab to "terrorize citizens."
Both countries pledged to cooperate in "undertaking security and military operations in the Lower Juba (border) regions of Somalia and to undertake coordinated pre-emptive action and pursuit of any armed elements that continue to threaten and attack both countries," the statement said.
The blast in Mogadishu hit the busy Kilometer 5 area near two hospitals and close to the foreign and planning ministries and about three kilometers away from where a meeting between high level Kenyan and Somali government officials had been taking place.
Al Shabaab had vowed to attack more government installations when they pulled out most of their fighters from Mogadishu and analysts had warned the insurgents would shift their tactics to more al Qaeda-style attacks.
The rebels claimed responsibility for an attack two weeks ago in Mogadishu which left more than 70 people dead, the biggest attack by al Shabaab since 2007 in Somalia, where they have been waging an insurgency to topple a government it sees as a puppet of the West.
The rebels have urged Somalis to pick up arms and threatened retaliation against Kenya for the military operation, warning Nairobi they would take the "flames of war" back across the frontier if Kenya did not withdraw its troops.
"The Mujahideen and all Somalis should fight back (against the) Kenyan troops that have invaded us," a pro-Shabaab website quoted Sheikh Hassan Abdullahi Hirsi, a senior Al Shabaab official, as saying.
SHABAAB REPRISALS IN KENYA?
Kenya, East Africa's biggest economy, has long looked nervously at its anarchic neighbor and its troops have made brief incursions into Somali territory in the past. This week's incursion on a larger scale could invite reprisals.
"Al Shabaab has avoided attacks (inside Kenya) so far because it benefits too much from the illegal shipment of goods from Kismayu into Kenya and from financial supporters in the Somali community in Kenya," said David Shinn, a former U.S. ambassador to Ethiopia.
"Al Shabaab may conclude that the Kenyan action must be responded to, however, and the easiest way to do this is to carry out terrorist attacks inside Kenya. This would really ratchet up tension in the Horn," he said.
Separately, a Somali army general said rebels were holding two Spanish aid worker hostages, and had moved them north to their coastal stronghold Kismayu as Kenyan and Somali forces closed in.
"Al Shabaab is holding them in Kismayu," General Yusuf Hussein Dunmaal, who commands Somalia's southern forces, told Reuters by telephone.
The militants have denied responsibility for kidnapping the Spaniards, seized from a refugee camp in Kenya where they were assisting fleeing Somalis, or for two other kidnappings of Westerners in Kenya. They say the kidnappings are being used as a pretext to launch the cross-border operation.
Kenya also arrested two British citizens suspected of ties to Somalia's al Qaeda-linked rebels as they crossed the border into Somalia near to the coast.
(Additional reporting by Ibrahim Mohamed, Abdi Sheikh and Feisal Omar in Mogadishu, Richard Lough and Beatrice Gachenge in Nairobi; Writing by Yara Bayoumy)