Baghdad, Iraq (CNN) -- Iraq's Kurds Tuesday threatened to boycott national elections scheduled for next January, casting further shadows over a vote seen as a key landmark in Washington's plan to withdraw U.S. combat troops from the country.
The government in Iraq's autonomous northern Kurdish region warned it will pull out of the election unless a dispute over parliamentary seat allocations for the country's provinces was resolved.
Minority Sunni Arabs are also threatening the vote, raising last-minute objections to a long-awaited new election law that was passed earlier this month.
Officials are shooting for a January 18 election date and have already begun planning for the national elections, but authorities say results would lack credibility if Kurds and others decided not to cast votes.
Any hitch could also result in a postponement of promised U.S. troop withdrawals.
The United Nations' Iraqi mission, election officials and parliament members were Tuesday locked in efforts to tackle the latest issues in the hope of averting any further hitch.
Iraq passed its new election law on November 8 after months of wrangling, but the legislation needed unanimous approval from the country's three-member presidency council -- made up of Kurdish President Jalal Talabani, Shiite Vice President Adel Abdul Mehdi, and Sunni Arab vice president Tariq al-Hashimi.
Al-Hashimi Tuesday threatened to take the unusual step of exercising his veto because he says the law does not fairly represent Iraqi refugees, many of whom are Sunni Arabs who fled to Jordan and Syria because of sectarian warfare.
He said the country's constitution stipulates that there should be one seat in the parliamentary Council of Representatives for every 100,000 Iraqis, but, he said, this does not take refugees -- or minorities including Christians into account.
The Kurdish regional government meanwhile called for election authorities to revisit seat allocation, claiming some areas got more seats than they are entitled to in a deliberate effort to keep Kurds out of parliament.
Tuesday's developments reflect the persistent political jockeying among Iraq's three main ethnic groups for power in the upcoming parliament, which will increase in size from 275 to 323 seats because of population growth.