BAGHDAD (Reuters) - Iraq’s Supreme Federal Court on Sunday ruled against calls by Sunni and Kurdish lawmakers to delay a parliamentary election, expected to be called for May, to allow hundreds of thousands of people displaced by war to return home.

FILE PHOTO - Iraqi Prime Minister Haider Al-Abadi speaks during a joint news conference with French President Emmanuel Macron (not seen) at the Elysee Palace in Paris, France, October 5, 2017. REUTERS/Ludovic Marin/Pool/File Photo

Shi’ite politicians, including Prime Minister Haider al-Abadi, argued delaying the election would be unconstitutional.

The election must be held “within the timeframe provided by the constitution,” the court said in a statement.

Parliament is expected to meet on Monday to validate May 12 as the date for the ballot, as suggested by the government, or agree another date in May.

Abadi is seeking re-election, building on a surge in his popularity among Iraq’s majority Shi’ite Arab community after leading the three-year fight against Islamic State militants, supported by a U.S.-led coalition.

“Postponing the elections would set a dangerous precedent, undermining the constitution and damaging Iraq’s long-term democratic development,” the U.S. Embassy in Baghdad said in a statement on Thursday.

The United States had shown understanding for Abadi’s move in October to dislodge Kurdish fighters from the oil rich northern region of Kirkuk, even though the Kurds are traditional allies of Washington and played a key part in the war against Islamic State militants.

Tens of thousands of Kurds were displaced as a result of the takeover of the ethnically mixed areas of Kirkuk and its surroundings by Iraqi forces supported by Iranian-backed paramilitary groups.

The United Nations estimates the total number of people who remain displaced in Iraq at 2.6 million, mostly Sunni Arabs from areas previously controlled by Islamic State.

The role of prime minister is reserved for the Shi’ite Arabs under a power-sharing system set up after the 2003 U.S-led invasion that toppled Saddam Hussein, a Sunni Arab.

The largely ceremonial office of president is reserved for a Kurdish member of parliament, while the speaker of parliament is drawn from among Sunni Arab MPs.