By Ercan Gurses and Gulsen Solaker
ANKARA (Reuters) - Two Turkish opposition parties have pulled out of a commission meant to draft a new constitution, in protest at attempts by the ruling AK Party to strengthen the role of the presidency, something keenly sought by President Tayyip Erdogan.
Prime Minister Ahmet Davutoglu said on Wednesday the AKP would continue work on a new charter despite the withdrawal of the Republican People's Party (CHP), and urged other opposition parties to remain at the table.
But the Nationalist Movement Party (MHP) said it too would pull out of the commission if the CHP did not take part. MHP Vice President Oktay Ozturk told Reuters it would be wrong for the panel to continue work without the main opposition.
The AKP, founded by Erdogan more than a decade ago, has broad cross-party support for overhauling the constitution, which dates back to an era of military coups. But there are wide divergences over what a new charter should look like.
Erdogan and the AKP want the head of state, currently a largely ceremonial post, to wield much greater political powers. But opposition parties fear Erdogan is already becoming too authoritarian and, as well as opposing strengthening his office, they want the new constitution to focus on minority rights and democratic freedoms.
"The main opposition announced it won't participate in work on a new constitution because they're unwilling to bring issues such as the executive presidency to the table," Davutoglu said in a speech in the capital Ankara.
"We will continue to be at the table ... It is our duty to compromise on a new constitution without any prerequisites ... I call on all opposition parties to be at the table to be able to discuss any issue."
Western allies, which need Turkey as a stable partner in the fight against Islamic State and in efforts to resolve Europe's migration crisis, support the idea of a constitution that bolsters human rights and democracy but fear an executive presidency could strengthen Erdogan's authoritarian instincts.
The Islamist-rooted AKP temporarily lost its single-party majority in an election last June but, after coalition talks failed, it swept back to power in a snap poll five months later, capturing nearly 50 percent of the vote.
But it would need the support of 14 opposition lawmakers to put a new constitution to a referendum, and would require the backing of around 50 to change the constitution directly without the need for a popular vote.
Davutoglu and the CHP agreed at the end of December to revive the parliamentary commission, but there were already doubts over how much progress it would make.
A similar cross-party panel tried for two years to reconcile differences on some of the most divisive issues in modern Turkey. It agreed some 60 article changes, but gave up in late 2013 after running into insurmountable disagreements on issues ranging from the definition of citizenship to the protection of religious freedoms.
(Additional reporting by Asli Kandemir in Istanbul; Writing by Nick Tattersall; Editing by Robin Pomeroy)