Helicopters attack Colombian rebels as president visits south TORIBIO, Colombia (Reuters) - Colombian helicopter gunships strafed suspected rebel hideouts and guerrillas set up roadblocks as President Juan Manuel Santos visited the nation's volatile south on Wednesday amid growing criticism that security has deteriorated. Latin America's fourth-biggest economy has battled Marxist insurgents for nearly five decades, and despite a U.S.-backed crackdown that drove rebels into more remote hideouts, guerrillas have stepped up attacks in the last few years. Helicopters shot at fighters from the Revolutionary Armed Forces of Colombia, or FARC, holed up in the lush mountains of Toribio municipality in the southern Cauca province before Santos landed, a Reuters photographer said. Santos - who was jeered on arrival by residents calling for security forces to withdraw - told the indigenous population that the government would not pull troops out of the area, which has seen heavy combat in recent weeks. You've said that you're tired of war. Not only you, I'm tired of war ... 46 million Colombians are tired or war, but in no way can we demilitarize even one centimeter of our land," he said after holding a security council meeting with ministers. A short distance from the town center where Santos and his ministers met, guerrillas had set up a makeshift checkpoint with five or more camouflaged rebels standing on the road. "The idea is to let the people see that what the government says isn't true," a FARC fighter, who went by the alias of Johan, told reporters. What the president says to the media is that the FARC are defeated, that they're at their end. With this checkpoint, we're showing the media and the people, that's a lie. Cauca province has been one of the most intense regions of the conflict and is a strategic area for production and transport of cocaine. Before Santos arrived, police disarmed explosives that had been placed in a field where his helicopter was expected to land, local media said. In July last year, rebels set off a bus bomb in Toribio, wounding more than 60 people and destroying hundreds of homes. Two years after Santos took office, the bloody resurgence of left-wing guerrilla attacks and a botched reform have cut into his once-commanding approval rate. In the first four months of 2012, attacks by illegal armed groups shot up 57 percent to 58 incidents compared with the same period last year - the highest level since 2006, according to defense ministry data. Opponents say Santos is dropping the ball on security issues, allowing the FARC, Latin America's oldest rebel group, to recoup some of the ground lost during a military offensive under former President Alvaro Uribe. Uribe, who chose Santos as his defense minister and then backed his run for president, has become his fiercest and most potent critic. Analysts, however, say that security improvements since 2002 were starting to be reversed during Uribe's second term from 2006 to 2010 after gains from better intelligence, air power and reform reached their peak and the FARC adjusted tactics. Security is still vastly better than a decade ago and that has helped attract record levels of investment, mainly in oil and mining. Colombia expects to see foreign investment of $16 billion this year, compared with about $2.1 billion in 2002. But security worries are hurting Santos' popularity. The latest Gallup poll showed his approval rating dropping to a low of 48 percent, while another saw him fall 5 points to 66 percent - compared to 76 percent in late 2010 after troops killed FARC military leader Mono Jojoy. "With ... clear signs that the government has failed to adequately follow up military successes with investments and assertions of control in various departments, the security outlook for this year is not promising," Heather Berkman, an analyst with Eurasia Group, said in a note. Until real progress is made on this, Santos will struggle to recoup his approval ratings and he will remain politically vulnerable. Reporting by Jaime Saldarriaga in Toribio and Jack Kimball and Monica Garcia in Bogota.; Writing by Jack Kimball.; Editing by Helen Murphy and Christopher Wilson