The Palestinian Authority president has set 26 July as the date for a controversial referendum on a statehood plan that implicitly recognises Israel.
Tensions between Hamas and Fatah have worsened recently
Mahmoud Abbas made the announcement in an official decree.
The Hamas movement, which leads the government, has rejected the proposal saying such a vote would be illegal.
The plan sets out formal Palestinian claims to an independent state on land occupied by Israel in 1967, and implicitly adopts a two-state solution.
The referendum will be non-binding.
The announcement was immediately denounced by Hamas.
Leading Hamas official Mushir al-Masri denounced the proposal as nothing short of a "a declaration of a coup against the government".
"Whoever announced the referendum should shoulder the responsibility for the dangerous consequences that may result," he said, adding that Palestinians should boycott the vote.
Hamas would "try to prevent this referendum from taking place by all legal means" he was quoted as saying by the news agency AFP.
There has been increasing tension between Mr Abbas and his formerly dominant Fatah party since Hamas won a landslide victory in January's general elections and took over the government.
Hamas, which does not recognise Israel and actively works for its destruction, has warned that putting the issue to a referendum could cause divisions within the nation.
"The idea of a referendum carries serious dangers for the unity of the Palestinian people, and I fear that it may provoke an historic division that will take decades to overcome," Prime Minister Ismail Haniya wrote in a letter sent to the Palestinian president earlier this week.
By contrast, Mr Abbas and his Fatah movement does recognise Israel and backs the establishment of a Palestinian state in the West Bank and Gaza.
Mr Abbas had given Hamas until the end of the week to agree to the plan or said he would put it to a public referendum.
On Thursday, he met with Hamas cabinet ministers but the talks ended without any progress.
The 18-point plan was drawn up by Palestinians from various factions who are serving time in Israeli prisons.
It calls for continued resistance on lands occupied by Israel in 1967, but proposes an end to attacks inside the area internationally-recognised as Israel.