Boko Haram jihadists have killed four farmers near the northeast Nigerian city of Maiduguri, in the latest bloodshed in the restive region, witnesses and a local militia leader said on Monday.Dozens of fighters believed to be loyal to Boko Haram factional leader Abubakar Shekau attacked a group of farmers working in their field near Jiddari-Polo on Monday, said the farmers who survived the attack.They said the Islamists hacked their victims to death and left another farmer with severe injuries."They came in large numbers on foot while we were picking cowpea in the field and arrested six of us while others escaped," Mala Umara told AFP."They macheted four to death before my eyes and left the other man seriously injured," he said.A civilian militia leader in the city, Babakura Kolo confirmed the killings.Umara, 75, was spared by the militants with a message to Nigerian troops stationed in Jiddari-Polo that they should brace for an impending attack from the jihadists.'I was too fast for them' "They asked me to deliver a message to the soldiers that they should be prepared for an attack soon."They told me the same message three times and emphasised I convey it to the soldiers," Umara said.Abba Muhammad was also among the farmers who escaped when the militants stormed the crop fields."Five of them armed with guns and machetes encircled me and began asking me the location of soldiers in Jiddari-Polo," he said."One of them shouted that they should attack me with machetes but I instinctively bolted."Two of them pursued me but I was too fast for them. They took my bicycle with them," he said. Authorities in the region could not be immediately reached about this latest attack.Boko Haram has stepped up attacks on farmers and loggers in recent years, accusing them of passing information about the group to the military. Last week, the jihadists killed nine farmers and abducted 12 others in an attack on Mammanti village near Maiduguri.* Sign up to News24's top Africa news in your inbox: SUBSCRIBE TO THE HELLO AFRICA NEWSLETTERFOLLOW News24 Africa on Twitter and FacebookOn November 16, the insurgents kidnapped 50 loggers near the town of Gamboru on the border with Cameroon, four days after 15 farmers were shot dead as they worked in their fields near the garrison town of Monguno, 140km from Maiduguri.Last month the jihadists hacked 12 farmers to death in Kalle, a remote village 17km from Maiduguri. Despite the government's insistence that Boko Haram are near defeat, the group has recently carried out major attacks on military and civilian targets, killing scores.Security sources said at least 44 soldiers were killed in an attack in Metele village, near the border with Niger, last week, although one soldier who escaped gave a higher toll.AFP has reported at least 17 attempts to overrun army bases since July. Many have been claimed by the ISIS-backed Boko Haram faction, Islamic State West Africa Province (ISWAP).More than 27 000 people have died since the start of the insurgency in the remote northeast in 2009 and 1.8 million are still homeless.