MAPUTO (Reuters) - Seven soldiers were shot dead when gunmen raided a weapons depot in Mozambique, local newspapers and a security source said on Tuesday, the latest ambush and attack on security forces to rekindle memories of the 1975-1992 civil war.
The assault, which took place on Monday, forced hundreds to flee the central town of Savane and interrupted rail traffic on the nearby Sena line, the southern African nation's sole coal export route, said a spokesman for Brazilian mining firm Vale.
Local newspapers, including the O Pais daily, said guerrillas from the opposition Renamo party were behind the attack, although a source familiar with Mozambique security said it appeared to be the work of a Renamo splinter group.
A Renamo spokesman said the party was investigating the incident and did not claim responsibility.
The Defence Ministry declined to comment until it had gathered more information.
Relations between Renamo, founded around independence in 1975 with the backing of white-ruled Rhodesia and apartheid South Africa, and Frelimo, the ruling, formerly Marxist party, have become increasingly tense.
Two months ago, Renamo fighters killed four policemen in an attack on a police station and a few days later three civilians were killed when gunmen ambushed vehicles on the main north-south highway, a common Renamo tactic during the civil war.
Analysts say Renamo, which has vowed to disrupt local elections this year and a presidential poll in 2014, has at most 1,000 armed men under its command and poses no significant military or political threat to Frelimo.
However, many Mozambicans fear even the slightest violence could upset the political stability that has underpinned an unprecedented economic boom based on foreign investment in coal mining and natural gas exploration.
The off-shore Rovuma field is believed to hold enough gas to supply Germany, Britain, France and Italy for 15 years, and mining giants Vale and Rio Tinto have invested nearly $10 billion (6.4 billion pounds) in mines in Tete province, home to some of the world's largest untapped coal deposits.
Reporting by Marina Lopes; Editing by Ed Cropley and Elizabeth Piper