Suspected jihadist fighters have killed 12 people in northern Mozambique as they shift attacks to vehicles despite increased army patrols on main roads.Most of the victims died in attacks on cars and buses in the gas-rich, Muslim-majority Cabo Delgado region where Islamist militants have terrorised villagers in remote communities for more than a year.The murders mark a shift in strategy that had previously targeted isolated homes.Four people were killed early Saturday and four others wounded while driving near the town of Manilha, according to a police officer based near Mocimboa da Praia, in one of the worst-hit zones.On January 6, seven others were murdered in nearby Ulumbi after their bus was ambushed by a group of gunmen who torched the vehicle, local sources said.Another person was murdered and chopped up in the rice-growing area of Nailwa, five kilometres (three miles) from Palma, a district capital.The military has begun to escort public transport vehicles but they have nonetheless come under attack, said the policeman who asked not be named because he had no authority to speak to the media.* Sign up to News24's top Africa news in your inbox: SUBSCRIBE TO THE HELLO AFRICA NEWSLETTERFOLLOW News24 Africa on Twitter and Facebook. The policeman told AFP that drivers and passengers now preferred to travel without soldiers because their presence actually made them a more likely target.Hardline Islamists had mostly staged knife and arson attacks since October 2017, stoking unrest as Maputo pushes ahead with oil and gas development in the region.More than a hundred civilians have been killed during the raids and thousands more forced to leave their homes."The order of the attackers is (for people) to leave the villages," a local community leader who also asked to remain anonymous for fear of repression by the police, told AFP. "They say that these are liberated zones, they do not want people to live here," said the village leader added. Mozambican President Filipe Nyusi has underscored his determination to "neutralise" Islamists.Human Rights Watch (HRW) last month accused security forces of serious human rights violations and several journalists have been arrested in the area.