Iraqi Kurdish president Massoud Barzani is to step down as the region wrestles with Baghdad over independence.
In a bitter TV address, he defended the independence referendum he called.
An overwhelming majority of voters approved secession, triggering fighting with Iraqi government troops who seized Kurdish-held oil rich areas.
As parliament debated his decision to stand down, some pro-Barzani supporters forced their way into the building to protest against his treatment.
The details of the situation remain unclear, but some witnesses reported seeing protesters with clubs, and some gunshots have also been heard.
Some Kurds are aggrieved that the 71-year-old leader's dream of Kurdish independence has been left in tatters, despite wide support within the region in the 25 September referendum.
On Sunday, Mr Barzani confirmed in a letter that he would not seek an extension to his presidential term, which ends in four days.
The majority of the region's MPs supported Mr Barzani's decision to step down.
What did he say in the speech?
In a speech aired on Kurdish TV after he submitted his letter to parliament, Mr Barzani said: "Three million votes for Kurdistan independence created history and cannot be erased."
He accused rivals of committing "high treason" for abandoning the oil-rich city of Kirkuk to central Iraqi forces without a fight.
He also pointed to the Peshmerga Kurdish fighters' role in the battle against the Islamic State.
"Without the help of Peshmerga, Iraqi forces could not have liberated Mosul," he said, referring to IS's former stronghold, which fell earlier this year.
A gamble that backfired
Analysis by Arab Affairs Editor Sebastian Usher
It's been a tumultuous day in Kurdistan as the long era of Masoud Barzani appears to be coming to an end.
With his sturdy frame always clad in the khaki uniform and red and white head dress of a peshmerga fighter, Mr Barzani has been a symbol of Kurdish nationalism for decades.
He is stepping down just weeks after he took the biggest gamble of his 12 years as president - an independence referendum. He had judged the time was right to achieve the Kurds' most cherished dream with their forces having proved their mettle against the Islamic State group.
But the move backfired dramatically, with Iraqi forces responding by reversing the Kurds' territorial gains of the past three years.
Barzani's Life and Times
Born in a Kurdish area of Iran in August 1946, he is the son of the founder of the Kurdistan Democratic Party (KDP), Mustafa Barzani.
Massoud Barzani took control of the KDP on his father's death in 1979. He became president of Iraqi Kurdistan in 2005, having played a key role in creating an autonomous territory after Saddam Hussein fell in 2003.
He went on to win another presidential election in 2009, and his term was extended in 2013. After Iraqi military reclaimed the disputed, oil-rich province of Kirkuk earlier this month, he faced calls to stand down.
Presidential and parliamentary elections due for 1 November were suspended when the Kirkuk assault started.