MAPUTO — Britain advised citizens on Tuesday against travelling to an area in northeastern Mozambique after a series of attacks by groups with links to Islamic militants.

At least 17 people have been killed – 10 of them beheaded -since May in the town of Palma, near the Tanzanian border. The UK joins in the United States in issuing a warning about the attacks.

“The Foreign and Commonwealth Office advise against all but essential travel to the districts of Palma, Mocimboa de Praia and Macomia in Cabo Delgado province due to an increase in attacks by groups with links to Islamic extremism,” the office said in a warning posted on its website.

Palma is near one of the world’s biggest untapped offshore gas fields, and Anadarko Petroleum is seeking to raise US$14 billion (10.47 billion pounds) to US$15 billion for a liquefied natural gas project in the region.

The company has said it was monitoring the situation. It declined to comment on reports that it has suspended work on its project.

Canada-based Wentworth Resources said the security situation was part of the reason it sought a one-year extension for its appraisal licence in the region.

“This has prevented safe access to the area for Wentworth staff and contractors. The Company continues to monitor the situation closely,” it said in statement posted on its website.

Six men wielding machetes killed at least seven people and injured four others this month in the predominantly Muslim region. Ten people were beheaded last month, and local media reported at least two were children.

Mozambique has not been a focal point of Islamist militant activity in the past and police have been reluctant to ascribe the attacks to Islamists. About 30 percent of Mozambique’s 30 million people are Roman Catholics; about 18 percent are Muslim.