Banjul - Voters in the tiny West African nation of Gambia cast marbles on Thursday in an election widely expected to keep the country's ruler of more than two decades in power despite a unified effort by the opposition.President Yahya Jammeh has vowed not to allow protests of any kind, and the country's phone and internet services were cut hours ahead of polling stations opening in an effort to thwart unrest."This will be the biggest landslide in the history of the country," Jammeh said on Thursday after voting with his wife in the capital. He was met with cheers as he walked toward his sports utility vehicle and refused to comment when asked whether he would concede in the event of defeat.His challenger Adama Borrow said he believed Gambians were ready for change after more than 20 years of the Jammeh regime."He is not going to be re-elected - his era is finished," Barrow said.Most voters refused to comment on which candidate they were backing. Inside polling stations, each person places a marble in either a green, silver or purple drum depending upon their choice.The African Union sent a handful of observers to this country of 1.9 million but there are no observers from the European Union or the West African regional bloc Ecowas because the Gambian government did not grant them accreditation.Jammeh came to power in a coup in 1994, and then swept elections in 1996, 2001, 2006 and 2011, after a 2002 constitutional amendment removed presidential term limits. Critics, though, say those elections were not free and fair, and they accuse his regime of corruption and human rights abuses.The longtime leader has said that his victory is all but assured with divine intervention. Demonstrations will not be allowed "because those are the loopholes that are used to destabilize African governments," he said.Jammeh's supporters praise his efforts to boost economic development in the small country that is dependent on tourism and agriculture."He has built the airport, schools, medical facilities and buildings," said 50-year-old Pinta Manneh, smiling with excitement for the man she was certain would be re-elected for a fifth term. She couldn't imagine an opposition victory. "He will be angry if he loses," she said.Barrow, a former businessman and United Democratic Party leader, emerged as the candidate for an alliance of eight opposition parties. Former ruling party deputy Mama Kandeh is running for the Gambia Democratic Congress, the only opposition party not in the coalition.Security forces arrested dozens in April and May after protests calling for electoral and political reforms. Two main opposition party members died in detention after the protests, and 15 opposition supporters are now serving three-year prison sentences.Omar Amadou Jallow, an emblematic opposition leader for the People's Progressive Party, which joined the coalition, says despite that clampdown this is the year for change."For 22 years we have realized that Gambia has been turned into a prison; the arrests, the tensions, the torture and many of our people have gone into exile ... That shows the tyranny of the regime," he said. "We are going to give people their freedoms, their liberties. That is more important than anything else."