* Putin's visit asserts Moscow's presence in North Caucasus
* Human rights groups slam Kadyrov's tough methods
(Adds rally in Moscow, human rights groups' comments)
MOSCOW, Aug 24 (Reuters) - Vladimir Putin visited Russia's restive Chechnya region on Monday, showing support for a local leader accused by rights groups of abuses and demonstrating Moscow's presence in a mainly Muslim region racked by violence.
Central Russian channels showed Prime Minister Putin and Kremlin-backed regional chief Ramzan Kadyrov alighting from a military helicopter at Tsentoroi, the Kadyrov clan's home village in the southeastern Chechen foothills.
Putin launched a second war to crush Chechen rebels in 1999 that gained him widespread popularity and propelled him to the highest office. Violence has flared again in the past months, with attacks by militants seeking an Islamist state in the north Caucasus spreading to neighbouring Dagestan and Ingushetia.
Surrounded by heavily armed guards in camouflage and with sub-machineguns at the ready, the two men laid a basket of red and white roses at the tombstone of Kadyrov's father, Akhmad, who was killed in a bomb blast in 2004.
"It is thanks to this courageous man that the war ended. He gave his life for Russia and Chechnya," a sombre Putin said, to a roar of helicopter gunships patrolling the area.
Kadyrov faces strong criticism from human rights bodies after kidnappings and killings of human rights and charity activists in Chechnya. He denies any link to killings.
His tough methods used in fighting the rebels are also under international scrutiny and have been blamed by critics for the spread of insurrection. Kadyrov has amassed enormous personal power in the region that some analysts say could eventually pose a renewed threat to Kremlin control.
In Moscow, some 50 human rights activists held a rally in heavy rain to commemorate Chechen activist Natalia Estemirova, killed 40 days ago. "Kadyrov resign!" they chanted.
"People have become truly afraid to report abuses in Chechnya," Allison Gill, Russia director at the New York-based Human Rights Watch (HRW), told journalists.
"It is clear that the situation there (in Chechnya) has gone out of control ... The government bears the responsibility for the security situation. Obviously there is a lot of fear of the security services and of Kadyrov," she said. "He has got to go."
Last Monday, a powerful truck bomb exploded at a police headquarters in Ingushetia, killing at least 25 people and dealing a humiliating blow to Moscow's authority in the region.
Ingush President Yunus-Bek Yevkurov, seriously wounded in a suicide bomb attack on June 22, resumed his duties at the weekend.
Suicide bombers on bicycles launched two separate attacks on Friday, killing at least four policemen, in the Chechen capital Grozny, newly rebuilt after two devastating secessionist wars.
Akhmad Kadyrov, like his son, was a rebel who fought against federal forces in the first Chechen war. He became Chechen leader after switching sides shortly after Putin launched the second war to crush the rebel government.
"His life was not lived in vain and he died for a cause," Putin said. "In fact, he saved ... the lives of a great many people, because he laid a foundation for peace in Chechnya. We will remember him forever."
Putin has taken a consistently tough line on secessionism -- a sensitive issue in a country that spans 11 time zones from the Baltic Sea to the Pacific Ocean and embraces dozens of ethnic and religious groups.
A worker at Russia's Memorial human rights watchdog, who had worked with Estemirova, told reporters on condition of anonymity: "The situation in Chechnya now, the atmosphere, is simply wretched. It is just awful."
"Putin gave Kadyrov 'carte blanche' to act in whatever way he wants. What is in fact happening is this in turn creates new rebels, and creates militants, who are fighting for both sides". (Additional reporting by Amie Ferris-Rotman; Writing by Dmitry Solovyov; Editing by Ralph Boulton)
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