Uganda's President Yoweri Museveni on Sunday celebrated extending his three decades in power with a walk with his beloved cows, dismissing opposition claims of poll rigging and criticism by the international community. Uganda's veteran leader was declared the winner of the country's presidential election with 60 percent of the vote on Saturday, far ahead of the 35 percent won by detained opposition chief Kizza Besigye, whose house was surrounded by police in riot gear as the results were announced. "The opposition are not leaders, they are just demagogues, liars, just talking, talking," the 71-year-old Museveni said Sunday in a speech broadcast from his home in western Uganda, his first comments since winning.