Sept. 25 (Bloomberg) -- Pakistani President Asif Ali Zardari disputed a NATO account that his country's forces fired at coalition helicopters along the border with Afghanistan, saying they had shot only flares as a warning.

``They're flares,'' Zardari told reporters today before stepping into a meeting with Secretary of State Condoleezza Rice in New York. ``They're just to make sure that they know they crossed the border line. Sometimes the border is so mixed that they don't realize that they crossed the border.''

The North Atlantic Treaty Organization aircraft weren't hit by the small-arms fire from a military border checkpoint near the Tanai district in Afghanistan's eastern Khowst province, NATO said in an e-mailed statement. The alliance said it was working with the military in Pakistan ``to resolve the matter.''

``At no time did ISAF helicopters cross into Pakistani airspace,'' NATO said. The alliance said it would release more information as it became available. NATO heads the International Security and Assistance Force, or ISAF, in Afghanistan.

The incident may add to tension between the West and Pakistan, which has blamed U.S.-led forces in Afghanistan for conducting several cross-border raids against suspected terrorist targets. Zardari declared this month that such operations are a violation of sovereignty and would no longer be tolerated.

Pakistan's military said Sept. 16 it reserves the right to retaliate in self-defense and ordered army units to bring a halt to cross-border incursions. Yesterday the military said a U.S. spy plane malfunctioned and crashed in the tribal region of South Waziristan while flying over the border area.

Fighters, Weapons

Afghan and NATO forces have struggled to stem the flow of fighters and weapons across the mountainous 2,430-kilometer (1,510-mile) border, which fuels the Taliban-led insurgency aimed at toppling Afghan President Hamid Karzai.

U.S. Defense Secretary Robert Gates told the Senate Armed Services Committee in Washington this week that the Pentagon has presidential permission to strike Taliban and al-Qaeda targets in Pakistan. He said the United Nations charter gives a nation the right of self-defense when a foreign government is unable or unwilling to deal with terrorists inside its borders.

Zardari met two days ago with President George W. Bush in New York, where the two leaders attended the UN General Assembly.

``Your words have been very strong about Pakistan's sovereign right and sovereign duty to protect your country, and the United States wants to help,'' Bush said before the meeting.

Pakistan has ``problems'' it is working to resolve, Zardari said. ``We should come together in this hard time and we will share the burden and responsibility with the world.''

To contact the reporter on this story: Patrick Donahue in Berlin at at pdonahue1@bloomberg.net; Viola Gienger at the United Nations at vgienger@bloomberg.net

Last Updated: September 25, 2008 11:47 EDT