Kuwait has expressed dismay to the United Nations over a protest by stone-throwing Iraqis against the demarcation of the border, state media reported, underlining lingering tensions between the Arab neighbors a decade after Saddam Hussein was overthrown.
Iraq formally accepted a U.N.-demarcated border line in 1994 after the first Gulf War - when Iraqi strongman Saddam sent his troops into Kuwait in 1990 and was forced out by a U.S.-led coalition.
But many Iraqis in the area remain opposed to it, saying the line robbed them of property and territory.
Iraqi police sources said the protesting crowd hurled stones at Iraqi security forces in the border town of Um Qasr on Monday, prompting the security forces to fire in the air to disperse them. The unrest was triggered by border signs maintenance work nearby, they said.
Kuwaiti border guards, hearing the gunshots and believing they were being targeted, opened fire at Iraqi security forces in response, Kuwaiti media reported. There were no reports of casualties on either side.
Kuwait's Foreign Ministry undersecretary, Khalid al-Jarallah, said his country has submitted a memorandum to the United Nations and to Iraq over the incident, according to Kuwait's state news agency KUNA.
"We have issued a statement expressing our dismay over the irresponsible act,'' he said. "It is an act that runs counter to the nature of brotherly relations between Kuwait and Iraq.''
Kuwait pulled its border guards out of the area after the incident "to calm the situation'', Kuwaiti newspaper Al-Rai reported on its website.
KUNA said some of the protesting Iraqis had obstructed U.N.-supervised border signs maintenance and removed the border fence between two signs.
An Iraqi police source told Reuters that one activist was injured in the border unrest.
Leaders of both oil-producing countries have been working to improve ties in the past year, despite public wariness. The nations came to an agreement over Gulf War-era debts last year.
Iraq's foreign and transport ministers travelled on the first flight of state-run Iraqi Airways to Kuwait since 1990 last month, in a symbolic gesture hailed by officials as a sign of improving relations.
Kuwait's ruler and Iraq's prime minister have also visited each other's countries and officials have vowed to work together to maintain border markings.