Washington, Jan 10 (Agencies): US President Barack Obama has welcomed the peaceful start to the vote in Sudan on an independence referendum for the south, saying that the world is watching the development closely.

"This is an historic step in the years-long process to fully implement the Comprehensive Peace Agreement that ended the civil war between north and south," Obama said in a statement.

"We know that there are those who may try to disrupt the voting. Voters must be allowed access to polling stations, and must be able to cast their ballots free from intimidation and coercion," he said, adding that all sides should refrain from inflammatory rhetoric or provocative actions that could raise tensions or prevent voters from expressing their will.

"Violence in the Abyei region should cease. And while a successful vote will be cause for celebration, an enormous amount of work remains to ensure the people of Sudan can live with security and dignity," he said.

“The world will be watching in the coming days, and the United States will remain fully committed to helping the parties solve critical post-referendum issues regardless of the outcome of the vote."

US Secretary of State Hillary Clinton, in a statement, termed the start of referendum as a historic step towards implementation of Sudan's Comprehensive Peace Agreement.

People of Sudan deserve a process that is credible, peaceful and that ultimately reflects their will. Significant progress has been made in recent months towards preparing for the referendum, including the successful completion of voter registration and other technical arrangements, she added.

"We welcome the leadership shown by both parties to the CPA, including the commitment by President Bashir that his Government will respect the outcome of the referendum. We also appreciate the parties' acknowledgment of the importance of continued cooperation regardless of the outcome. This spirit will be important as the parties negotiate the post-referendum arrangements that will define their future relationship."

The US is committed to the long-term security and prosperity of both north and south Sudan and it will continue to support the Sudanese people, the Secretary of State added.