Kenya's military will pursue Somali gunmen across the frontier who they say are responsible for a spate of kidnappings of foreigners, the internal security minister said Saturday.
"Our territorial integrity is threatened with serious security threats of terrorism, we cannot allow this to happen at all," said Internal Security Minister George Saitoti, accusing Somali Islamist Shebab rebels of the attacks.
"It means we are now going to pursue the enemy, who are the Al-Shebab, to wherever they will be, even in their country," he told reporters.
Two Spanish aid workers were seized Thursday by gunmen and are believed to have been taken across the border into war-torn Somalia, the third incident of foreigners being abducted in Kenya in just over a month.
"If you are attacked by an enemy, you are allowed to pursue that enemy until where you get him," said Kenyan Defence Minister Yusuf Mohammed Haji, speaking alongside Saitoti. "We will force them far away from our border."
Security forces were still searching Saturday for the two Spaniards, both logistics officers with the aid group Medecins Sans Frontieres (MSF, Doctors Without Borders), who were abducted from Kenya's Dadaab refugee camp.
"The militants are still being pursued," Saitoti said. "We have mobilised adequate security forces who are still pursuing them."
Large numbers of Kenyan security forces including helicopters were reported close to the Somali frontier on Saturday, an AFP reporter in area said.
Kenya is still reeling from the recent kidnappings of a French and a British national from coastal regions, which has dealt a blow to its key tourism sector.
Aid agencies said they were halting all but life-saving relief efforts in Dadaab -- the world's largest refugee camp, and home to some 450,000 mainly Somali refugees fleeing drought, famine or war -- as they reviewed security.
Kenyan authorities have on several occasions expressed fears Islamist extremists would infiltrate the Dadaab camps from Somalia, as the border lies barely 100 kilometres (60 miles) away.
Kenya also said it had shut its border with Somalia, although enforcing that move across the porous frontier will be a near impossible move in reality.
"We have closed the border with Somalia and we have no apology to make," Saitoti said, adding that security officials would search all refugees entering and already in Kenya, claiming not all were "a bona fide refugee".
"This influx of refugees crossing over from Somalia is putting our country at risk, and we can't sit back and watch," he added. "We are going to embark on a thorough screening of the refugees."
The Dadaab camp complex has seen a huge influx of people this year -- over 7,500 people have arrived in the crowded complex of rag, tin and plastic huts this month alone.
The exodus has been sparked by a severe drought that has affected more than 13 million people across the Horn of Africa, hitting Somalia especially hard.
"Why is it that this refugee issue is being seen as a Kenyan issue?" Saitoti added.
"We want the international community to stabilize Somalia so that these refugees can be taken back there," he said.
Somalia has had no effective government ever since it plunged into repeated rounds of civil wars beginning in 1991, allowing a flourishing of militia armies, extremist rebels and piracy.
Although Kenya blames the extremist Shebab for the attacks, analysts say the work could also be the work of pirates, bandits or opportunistic criminal gangs.
The Shebab have reportedly denied involvement in the kidnappings, according to the World Health Organisation's representative for Somalia.