The Iraqi prime minister, Haider al-Abadi, says he is prepared to intervene militarily if the Kurdish region’s planned independence referendum results in violence.

In an interview with the Associated Press on Saturday, Al-Abadi said if the Iraqi population was “threatened by the use of force outside the law, then we will intervene militarily”.

Al-Abadi called the vote “a dangerous escalation” that will invite violations of Iraq’s sovereignty.

Iraq’s Kurdish region plans to hold the referendum on 25 September in three governorates that make up their autonomous region and in disputed areas controlled by Kurdish forces but claimed by Baghdad.

The United Nations has urged the Iraqi Kurdish leader, Masoud Barzani, to drop plans for the independence referendum and enter talks with Baghdad aimed at reaching a deal within three years.

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 seen by Agence France-Presse, he proposed “structured, sustained, intensive and result-oriented partnership negotiations ... on how to resolve all the problems and outstanding issues” between Baghdad and Erbil, the Kurdish region’s capital.

The Kurdish Regional Government (KRG) 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.

Kubis called for talks, overseen by the UN Security Council, that would aim to reach a deal 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 said.

He added that he hoped to hear from Barzani “in the next two or three days”.

“I hope they will consider the options and I am waiting for their answer,” he said.