Warri - While Nigeria's president Muhammadu Buhari was receiving treatment in London for an undisclosed illness, his energetic deputy Yemi Osinbajo was wooing the country's oil heartland. In stark contrast with Buhari, a 74-year-old former general who rarely ventures outside the capital, Abuja, the vice-president went on a whirlwind tour around Africa's most populous nation. Out of all his stops during Buhari's 49-day absence, Osinbajo's trips to the Niger delta - the oil-rich southern swamplands that dictate Nigeria's economic fortunes - were the most productive.The result: a noticable thaw in frigid relations between locals and the federal government, and a lull in attacks on oil and gas infrastructure that hit production in the last year. "The issues are very clear, we need to act quickly and that is my submission," 60-year-old Osinbajo said during a town hall meeting held in the Delta state capital, Warri, in January.By February 25, the federal government had released 10 oil rebels who had spent more than two months in custody.One of them, Smith Bounanaowei, said: "I believe Osinbajo is a man that has tried in the peace process. "My advice to the federal government is for them to follow the steps of Osinbajo in bringing peace to the region," he told AFP at his home in Yenagoa, the state capital of Bayelsa.Hands-on approach Osinbajo's hands-on approach has among other things raised hopes among Niger delta leaders of a return of the "Egbesu" sword, which was controversially removed from a sacred waterside shrine earlier this year.The perpetrators were said to be Nigerian troops combing the creeks for the Niger Delta Avengers, the militant group responsible for most of the attacks in the last 12 months.Local leaders are also hopeful that construction will resume of a maritime university near Warri that was shelved when Buhari came to power in May 2015. "He (Osinbajo) is actually putting action to his words," said Udengs Eradiri, a former president of the Ijaw Youth Council, an umbrella body for youths in the Niger delta region. "We are grateful to him as he has come to the peace process with an open mind and a clear conscience."Much has been made about Osinbajo's engagement in the region, which was hit in the early 2000s by rebels also motivated by a desire to see a more equitable distribution of oil wealth for locals.The vice-president's style certainly seems more consensual than Buhari, whose military has called the militants "economic terrorists". Buhari sent in troops while Osinbajo pushed for talks.Nigeria's government maintains the vice-president is not ploughing his own furrow and is working with Buhari to implement his policy."Their role in the presidency is one. It is a ticket," one of Buhari's spokesmen, Femi Adesina, told reporters earlier in March. "Any attempt to begin to demarcate between the president and the acting president is (an) exercise in futility."Nevertheless, experts say Osinbajo's more collaborative approach -- notably his willingness to physically meet a variety of regional leaders on their home turf -- has been invaluable."Osinbajo has been busy meeting with local stakeholders, focusing on the oil communities rather than on the usual suspects, whose main concern is entitlement," said Dirk Steffen, a security analyst at the Risk Intelligence consultancy in Copenhagen.The question now is whether Buhari, who returned to Nigeria on March 10, can keep up the momentum.Fragile peace Just two weeks after Buhari's return, tension in the Niger delta already appears to be mounting.Some former militants from the previous insurgency who receive monthly 65,000-naira ($205, 190-euro) stipends to stop them taking up arms have complained that they have not been paid since December. "The ex-militants are starting to ask when will they be paid," said Dolapo Oni, Lagos-based energy researcher at Ecobank. On Friday, Buhari met Niger delta leaders in Abuja while Osinbajo was again in the region on his troubleshooting tour. Again he pledged a peaceful resolution to the crisis.Steffen, who tracks the region and maritime security offshore in the perilous Gulf of Guinea where high seas pirates are active, said the lull indicated a fragile peace."There are some indications, and a general sense of foreboding in many parts of the Delta, that the violent part of the militancy isn't over yet," he said. "Guns and explosives are readily available and the armed groups will not disappear overnight."