Accra - More than 500 Togolese nationals have sought refuge in neighbouring Ghana because of a government crackdown on opposition protests, the UN refugee agency said on Friday."So far, 513 asylum seekers have been registered by the Ghanaian authorities," UNHCR spokesperson Babar Baloch said in a statement.They crossed the border to Chereponi, Zabzugu and Bunkpurugu-Yunyuo in Ghana's remote northwest and most were staying with local families or in community centres, he added."Togolese seeking safety, including women and children, told UNHCR staff they had fled on foot, walking from their homes in Togo's Mango region, bordering Ghana," he said."They said they were fleeing human rights abuses after the recent political protests."Hundreds of thousands of people have taken to the streets of Togo since late August to call for the resignation of President Faure Gnassingbe and demand constitutional reform.Gnassingbe is the scion of Africa's longest-serving political dynasty. He took over power in 2005 after the death of his father, who ruled Togo for 38 years.A coalition of opposition parties wants the introduction of a two-term limit on presidential mandates and a two-round voting system.Last week, gangs of youths clashed with police and soldiers who were trying to prevent them attending demonstrations in defiance of a government ban.At least 16 people have been killed and scores more injured in the violence.Paddy Tetteh, from the Ghana Refugee Board, said the situation with asylum seekers was "very fluid"."At some point they were more than 600 but some have left. Before there were more men than women but now it's an equal number," he told AFP by telephone.The United States and France have both expressed concern about the violence and reports of militia forces being used to disrupt protests and intimidate civilians.They and West African leaders called for dialogue to end the deadlock.