Palestinian President Mahmoud Abbas warned that he will take "unprecedented steps" to end the political division between his West Bank-based autonomy government and the Hamas-run Gaza Strip.
Abbas did not explain, but could try to use financial pressure to extract concessions from the Islamic militant Hamas which seized Gaza from him in 2007.
Hamas spokesman Fawzi Barhoum said Thursday that "the language of threats and dictating orders" would not be accepted.
The escalating rhetoric comes ahead of a planned meeting between Abbas and President Donald Trump that will likely focus on a possible resumption of Israeli-Palestinian negotiations about Palestinian statehood. No date has been set, but a Palestinian advance team heads to Washington later this month.
Hamas control of Gaza weakens Abbas, undermining his claim that he speaks for all Palestinians.
Hamas drove pro-Abbas forces from Gaza in 2007, a year after winning Palestinian parliament elections. Since then, repeated attempts at reconciliation have failed. A national unity government set up by Abbas in 2014, after a deal with Hamas, never got off the ground in Gaza.
Hamas refused to relinquish control to pro-Abbas security forces, particularly at border crossings with Israel and Egypt, while Abbas refused to incorporate tens of thousands of civil servants and troops hired by the Hamas government since 2007 into a new administration.
Last month, Hamas set up an administrative committee for Gaza, further angering Abbas.
He signaled earlier this month that despite Hamas control, Gaza is economically dependent on payments from his donor-funded Palestinian Authority in the West Bank. Citing donor concerns, the Palestinian Authority slashed by one-third the salaries of former government employees and members of the security forces who had served under Abbas in Gaza before 2007.
These 60,000 ex-employees continued to receive salaries for staying home after the Hamas takeover, as a way of ensuring their loyalty to Abbas. However, their spending also helped support the Gaza economy, inadvertently propping up Hamas.
Earlier this week, the Palestinian Authority noted that it spent $17 billion in Gaza since 2007, including for salaries and development aid.
Abbas told Palestinian diplomats in Bahrain on Wednesday that this policy would change.
"These days, we are in a dangerous and tough situation that requires decisive steps, and we are to take these decisive steps," Abbas was quoted as saying by the official Palestinian news agency WAFA. "Therefore, we are going to take unprecedented steps in the coming days to end the division."
Barhoum accused Abbas of trying to pressure Hamas ahead of his meeting with Trump.