Preparations for a January national election in Iraq were halted Wednesday after Tariq al-Hashemi, Iraq's Sunni Arab vice-president, rejected a key provision of the country's election law.

Al-Hashemi is sending part of the law back to the Iraqi parliament for amendment. He wants more seats allocated to Iraqis who live abroad, the majority of whom are Sunni Arabs.

"My objection is not to the entire law, but only the first article in order to be fair to Iraqis living abroad," al-Hashemi said to reporters. "I hope that parliament will hold a vote soon on the suggested amendments so that elections can be carried out at their scheduled date."

Al-Hashemi holds veto power over legislation as he is one of three members of Iraq's presidential council.

While a vote has not been scheduled, it must be held by the end of January, as stipulated by the country's constitution. It was not clear when the parliament might discuss al-Hashemi's demand.

Qassim al-Aboudi, a member of the Iraqi electoral commission, said the commission had suspended all of its activities tied to the vote's preparations.

"The situation is very difficult, and it is clear now that this will affect the commission's procedures and for sure will push the elections back," al-Aboudi said.

Iraqi Prime Minister Nouri al-Maliki said al-Hashemi's move posed "a serious threat to the political process and democracy."

"It has no solid constitutional basis," a statement on the prime minister's website said. "The high national interests were not taken into consideration."

Al-Hashemi's call came one day after Kurdish Iraqis threatened to boycott the vote over a similar demand.

Kurdish leaders claimed Tuesday that they too are under-represented in parliament.

A delay of the vote could be a blow to Iraq's fledgling democracy, and to U.S. plans to withdraw American troops from the country. The U.S. has said it will begin withdrawing troops about 60 days after the vote.

Under the plan of U.S. President Barack Obama, all U.S. combat soldiers must leave Iraq by the end of August 2010. Remaining trainers and support troops must be out by the end of 2011.

The top U.S. commander in Iraq, Gen. Raymond Odierno, said Wednesday that the military can adjust its plans, and that no decision is needed until late spring.

With files from The Associated Press