Gunmen firing automatic weapons dragged two Italian Roman Catholic nuns from their home in rural Kenya and drove them into lawless Somalia in a rare cross-border kidnapping, officials said.

The nuns — Maria Teresa Olivero, 60, and Caterina Giraudo, 67 — were working on hunger and health programs in the northeastern town of El Wak, about six miles from the Somali border. Monday's kidnapping highlights concerns among regional security officials that chaos in Somalia could lead to troubles in neighboring Kenya, which is struggling to patrol the long and porous border.

The early morning abduction began when six gunmen firing automatic weapons hurled a hand grenade and fired a rocket at Kenyan police, said Aden Mohamed Isaqm, a local aid worker. The gunmen then seized the nuns and drove them to the border in three stolen vehicles.

"I have seen two expatriates in a car with militia surrounding them," said witness Shacban Mohamed Ali. "The two foreigners were very shocked."

In Italy, the missionary movement of the two nuns said efforts were under way to contact the kidnappers and negotiate the captives' release.

The kidnappers "didn't go there looking for money or something else. They specifically aimed to take those people. We don't know if there are political or ... other motives," said Father Pino Isoardi, the head of the Contemplative Missionary Movement of Father de Foucauld.

Speaking on Vatican radio, he said no contact had been made with the kidnappers. "However, we know that local elders and authorities are working to find a path to contact them," he said.

The movement was founded in Cuneo, northern Italy, in 1951, and later named after French Priest Charles de Foucauld, who worked as a missionary in Africa during the early 20th century.

The desert border of Somalia and Kenya where the kidnapping occurred is hundreds of miles (kilometers) long and crossed by thousands of Somali refugees every month.

American troops are training the Kenyan security forces in an effort to prevent extremists from crossing into the country.

Both sides of the arid border region are plagued by banditry and clashes among ethnic groups fighting for grazing and water rights. A recent drought has heightened tensions in an area awash with weapons smuggled from Somalia into Kenya.

The nuns had been working in Kenya for decades and were among the few non-Muslims in town, the Catholic Information Service said. They ran a small dispensary and offered medical care to malnourished children.

The Italian Foreign Ministry said its crisis unit was working to secure the nuns' freedom.

Somalia has not had a functioning government since clan-based warlords overthrew a socialist dictator in 1991, plunging the nation into chaos. For the past two years, a bloody Islamic insurgency has killed thousands of people, most of them civilians caught in the crossfire.

The current government is supported by Ethiopian troops, who ousted the Islamists from the capital and much of the south in December 2006.

The Catholic church has been the target of several attacks in Somalia, parts of which were once colonized by Italy.

In 2005, insurgents dug up remains in an Italian cemetery where around 3,000 people were buried, and threw them into the sea. The following year an Italian nun working in a hospital in the capital was shot dead. Earlier this year, residents of the southern town of Kismayo began destroying an abandoned Catholic church after the town was taken over by Islamic extremists.