Hundreds have demonstrated in eastern Iraq against a planned referendum on the secession of northern Iraq's Kurdish region, which neighbouring countries and Western powers fear could break up the country and stir regional ethnic and sectarian conflict.

Protesters, who gathered outside the Baquba city council on Sunday, waved banners denouncing the September 25 vote and called on local authorities to ban the polls.

"We are taking to the streets to express our rejection of this secession referendum," Salim Saleh, a protester, told Anadolu news agency.

The non-binding referendum will see Iraqis in areas under the control of the Kurdish Regional Government (KRG) - and in a handful of territories disputed between Erbil and Baghdad - vote whether to secede from Iraq.

Along with Baghdad, Turkey, the US, Iran and the UN have all spoken out against the poll, saying it will only distract from the ongoing fight against the Islamic State of Iraq and the Levant (ISIL, also known as ISIS) group and further destabilise the region.

On Saturday, four Iraqi Kurdish soldiers were killed in an explosion in the province of Kirkuk, an area where the referendum is set to be held, Iraqi police said.

Seven other Kurdish Peshmerga troops were injured in the blast that hit their patrol car, 250km north of the capital Baghdad, police added.

So far, there has been no claim of responsibility.

'Say Yes to free Kurdistan!'

Kurdish red-white-green tricolours set with a blazing golden sun adorn cars and buildings throughout the semi-autonomous northern Kurdish region.

Billboards exhort "The time is now - say 'yes' to a free Kurdistan!".

Masoud Barzani, president of the Kurdish region since 2005, has resisted efforts by the UN, the US and Britain to delay the referendum.

Neighbouring Turkey is holding army exercises on the border to underline its concerns that Iraqi Kurdish separatism could feed insurrection on its soil.

But Hoshyar Zebari, a senior adviser to Barzani, told Reuters news agency: "This is the last five metres of the final sprint and we will be standing our ground".

Many Kurds see the vote, though non-binding, as a historic opportunity to achieve self-determination a century after Britain and France divided the Middle East under the Sykes-Picot agreement.

That arrangement left 30 million Kurds scattered over Iran, Turkey, Syria and Iraq.

More than 5.2 million people are registered to vote.

Al Jazeera's Hoda Abdel-Hamid, reporting from Erbil, said despite fierce opposition from the Baghdad government and the regional powers, Kurds across northern Iraq will go ahead with casting their votes.

"What you've been hearing all along from Baghdad is actually threats and condemnation. However, the response from Kurds have been quite defiant throughout the week," she said.

"President Barzani has been travelling around the Kurdish region, he also went into some of the disputed territories with the same message that we will go on with the referendum.

"Many people here say that know that there will be difficulties and there will be threats but that is something they say was expected."

Condemning the vote as "provocative and destabilising", the US has urged renewed negotiations. This followed a week of escalating rhetoric between the Kurdish leadership and Baghdad, where parliament voted to reject the referendum.