The UN has urged Iraqi Kurdish leader Massud Barzani to drop plans for a controversial independence referendum and enter talks with Baghdad.
Jan Kubis, the top UN envoy in Iraq, offered international backing for immediate negotiations between the country's federal government and the autonomous Kurdish region.
In a document he delivered to Barzani on Thursday, Kubis proposed "structured, sustained, intensive and result-oriented partnership negotiations... on how to resolve all the problems and outstanding issues" between Baghdad and Arbil.
The Kurdish Regional Government (KRG) based in the northern city of Arbil is embroiled in long-standing disputes with the federal government over oil exports, budget payments and control of ethnically divided areas.
Iraqi Kurdish lawmakers on Friday approved holding the referendum in the face of fierce opposition both from Baghdad and the Kurds' international backers.
In the document seen by AFP, Kubis called for talks, overseen by the UN Security Council, that would aim to reach a deal within "two to three years" defining "principles and arrangements" for future relations between Baghdad and the KRG.
In return, Barzani's administration would agree to postpone the referendum at least until the end of negotiations.
"Here is this offer, if they accept this alternative, there will be negotiations," Kubis told AFP.
He hoped to hear from Barzani "in the next two or three days", the UN envoy said. "I hope they will consider the options and I am waiting for their answer."
After several rounds of negotiations in the past, Arbil has repeatedly accused the central government in Baghdad of failing to deliver on its promises.
Despite assurances of Security Council involvement in implementing any future accord, Barzani on Saturday reiterated at a meeting in Dohuk, in the west of Iraqi Kurdistan, that the referendum would be "neither called off nor postponed".
But he also said that "any real alternative" was welcome and the door was not closed to a negotiated settlement.
On Friday, the United States, despite its longstanding support for the Kurds and its alliance in fighting Islamic State group jihadists, sternly urged Arbil to call off its independence referendum.
"The United States has repeatedly emphasised to the leaders of the Kurdistan Regional Government that the referendum is distracting from efforts to defeat ISIS (IS) and stabilise the liberated areas," the White House said.
"Holding the referendum in disputed areas is particularly provocative and destabilising," it warned.
Washington has repeatedly offered to help negotiate a long-term settlement between Arbil and Baghdad, but regional leaders -- including Barzani -- have been increasingly frustrated that warm words have not led to a precise diplomatic timetable.
This week, top US envoy Brett McGurk was again in Arbil and attempted to persuade the Kurdish leader to call off the vote in exchange for a new diplomatic initiative.
Analysts say the referendum plan, which has stirred Arab-Kurdish ethnic tensions, could mark the end of an era of cooperation during which Baghdad and Arbil battled IS together after it seized swathes of northern and western Iraq in the summer of 2014.
In the region, Turkey and Iran fear the referendum could stoke separatist aspirations among their own sizeable Kurdish minorities.
Turkish President Recep Tayyip Erdogan has warned the vote could prove "a very, very bad thing" for the Iraqi Kurds, whose economy is heavily dependent on oil exports via a pipeline running through Turkey.
On Thursday, the Baghdad parliament fired the governor of the northern province of Kirkuk, Najm Eddine Karim, over his provincial council's decision to take part in the non-binding Kurdish referendum.
The oil-rich province is disputed by Baghdad and Arbil and home to diverse communities including Arabs and Turkmens who oppose the vote.
Underlining Iran's opposition, the head of an elite Revolutionary Guards unit, Qassem Soleimani, is in Suleymaniya, a security source said, and plans to stay on in the Iraqi Kurds' second city until the planned referendum date.