A woman is assisted to cast her vote during a referendum in Harare, Zimbabwe, Saturday, March, 16, 2013. The country is holding the referendum on a new constitution which will pave way for the adoption of the draft constitution as the country prepares to hold elections later in the year. Supporters of Zimbabwean President Robert Mugabe greet his arrival to cast his vote during the country's referendum in the capital Harare, Saturday, March, 16, 2013. The country is holding a referendum on a new constitution which will pave way for the adoption of the draft constitution as the country prepares to hold elections later in the year. (AP Photo/Tsvangirayi Mukwazhi) Zimbabwean President Robert Mugabe casts his vote for a referendum on a new constitution that all main political parties have backed in Harare, Saturday, March 16, 2013. Officials said polling was busy in populous districts after voting stations opened at 7.00 a.m. Zimbabweans wait in a queue to cast their votes during a referendum in Harare, Zimbabwe, Saturday, March, 16, 2013. HARARE, Zimbabwe (AP) - Zimbabwe's longtime political rivals came together to vote 'Yes' in a referendum to accept a new constitution Saturday, but the rare consensus does not guarantee an end to political violence and intimidation ahead of crucial elections later this year, the prime minister's party said. Constitutional reform was a key demand of regional leaders mediating in the southern African nation's decade-long political and economic crisis. Reform was also a requirement for fresh elections to end a shaky and acrimonious coalition they brokered after the last violent and disputed national polls in 2008. The new constitution allows for more democratic reforms that would curb long entrenched presidential powers and punish perpetrators of human rights violations. However, Tendai Biti, the third ranking official in Prime Minister Morgan Tsvangirai's party, said Saturday that political intimidation continued into the vote. Biti said the arrest of a senior provincial official for the Movement for Democratic Change party by President Robert Mugabe's loyalist police on Saturday, casts doubt on the prospect of free and fair elections slated for around July. Sampson Magunise, the party official in eastern Zimbabwe, was seized by four armed police before referendum polling stations opened at 7:00 a.m. No reasons for his arrest were given. "This is illegal and unacceptable but it is typical of the environment we are living in," Biti said. Magunise's arrest followed attacks on four party's supporters putting up referendum posters in the northern town of Kariba and scuffles between rival youth groups in Harare and the second city of Bulawayo on Friday. Past elections have been marred by violence and alleged vote rigging blamed mostly on Mugabe's ZANU-PF party. Both President Mugabe and Prime Minister Tsvangirai said they voted 'Yes' Saturday after all main party leaders called for the 170-page draft constitution to be adopted. "We will celebrate a 'Yes' vote but we cannot accept intimidation of any of our members and then declare an election to be credible," Biti said. Biti said regional polling observers will likely report Saturday's vote as acceptable compared to "low standards of behavior" expected of Zimbabweans seen at previous polls. "We can't accept mediocrity when it comes to elections that wouldn't be tolerated in other countries" during polling, he said. Mugabe said he voted 'Yes' to the home-grown constitution to show how Zimbabwe mapped out its own future without outside interference. "It gives us the right to determine together which way to govern ourselves," he said. Mugabe, 89, who led the nation to independence from Britain in 1980, has repeatedly accused Western governments of supporting efforts to oust him. Mugabe, who voted at a school in western Harare with his wife Grace and his daughter Bona, 22, said he wanted peace in all polling. "Those who want to fight are allowed to if they are boxers or wrestlers, but to go about beating people in the streets, that's not allowed," he said. Tsvangirai, 61, was thronged by supporters while voting at a junior high school south of Harare, said a 'Yes' vote marked a new turning point "and one of the most important historical steps" for the southern African nation after years of political and economic turmoil. He said it paved the way for a new chapter of the rule of law. His supporters who have been killed in political violence over the past decade "will rest in peace because this is the most important stage we have been fighting for," Tsvangirai said. I hope everyone will exercise their vote as a preliminary step to free and fair elections. Officials said polling was busy in populous districts, and small knots of voters turned out early in remote areas and less populated or wealthier suburbs. The voting day was announced exactly a month ago, and critics say voters were not given enough time to study the constitutional proposals in detail. About 9,400 voting stations were set up and 12 million ballot papers have been printed. Abigail Punungwe, a young mother with a baby on her back in a line at one voting station in Harare, said she hadn't read the 170-page draft constitution "but everyone is saying we must vote for it." Elections monitors say printed copies were woefully inadequate in the two main local languages. Many rural Zimbabweans don't speak or read English. Monitors also pointed to only 200 braille copies being produced for the country's 40,000 blind people. Cumbersome voters' lists were not used. The nation has 6.6 million registered voters, but on Saturday all Zimbabweans over the age of 18 carrying a valid citizens' identification document were able to vote during more than 12 hours of polling. Polling stations using indelible finger ink on the hands of those who have already voted will stay open later into the evening if voters are still in line at the closing time. Voting lines over 200 meters (300 yards) long in Harare had tapered off by Saturday afternoon. Munganyi Nyarai, a polling officer in the western Harare township of Mbare, said more young people voted early at her post than in usual elections. The draft constitution reduces presidential powers to pass authoritarian decrees and paves the way for a National Peace and Reconciliation Commission on past violence and human rights violations. It also strengthens the bill of rights to protect all Zimbabweans from "torture, cruel, inhumane and degrading treatment or punishment" that would be enforced by a new Constitutional Court with powers above the main existing highest court of appeal, the Supreme Court. In urging supporters to vote 'Yes,' Mugabe's party says the draft recognizes as irreversible the seizure of thousands of white-owned commercial farms which have since 2000 been handed over to blacks. Black empowerment programs and the taking of control of foreign-owned mines and businesses by locals would also be irreversible. Mugabe's party says the draft honors black guerrilla fighters who ended colonial rule after a seven-year bush war with white-led troops of the former colony of Rhodesia, as Zimbabwe was known before independence in 1980. Small groups who have campaigned for a 'No' vote say the referendum is a compromise that doesn't meet the aspirations for change of ordinary Zimbabweans. The constitution has been taken over by politicians and doesn't reflect the true wishes of the people. It is a betrayal of generations to come," said voter Philimon Jambaya, 23. Associated Press reporter Gillian Gotora in Harare, Zimbabwe contributed to this report.