Canberra: United Nations chief Ban Ki-moon said on Friday that he regrets that member nations have failed to agree on a comprehensive counterterrorism convention in the decade since the September 11 attacks on the United States.
Ban said the UN could have achieved more.
"We immediately started to agree on a comprehensive convention on international terrorism, but regrettably this has not come about today," the UN secretary-general told reporters in the Australian capital Canberra after attending a South Pacific leaders` forum in New Zealand.
Negotiations on such a legally binding convention have repeatedly broken down over definitions of what constitutes terrorism and who is a terrorist.
UN members have split into two camps over the Palestinians: the Arab world against Israel, United States and much of Europe. There is also a less prominent divide between the backers of Pakistan and those of its archrival India.
The world body has passed 16 separate conventions dealing piecemeal with types of terrorism including bombing, hijacking and use of nuclear materials.
The UN also passed a global counterterrorism strategy in 2006 that sidestepped the lack of agreement on a legal definition for terrorism.
But Robert Orr, chairman of the UN Counterterrorism Implementation Task Force, said the strategy combined with the various counterterrorism conventions have limitations.
"That strategy has operationally everything we need to fight terrorism with the backing of all the UN member states," Orr said. "What it doesn`t have is the legal enforceability of a convention in specific areas."
"Legally, international law covers almost everything that you would want it to cover. What it doesn`t is this gray area: If someone is accusing someone else of engaging in terrorist activities, there`s no clinical definition of whether or not they are," he added.
Ban said was proud of his part in the UN response to the al Qaeda attacks, including a resolution on September 12, 2001, strongly condemning the attacks as heinous and calling for international cooperation to prevent and eradicate acts of terrorism.
Ban, who has been UN secretary-general since 2007, was a UN official in New York when the World Trade Centre twin towers collapsed.
The 67-year-old former South Korean diplomat plans to fly from Australia to New York to attend a concert on Saturday in memory of the thousands of victims who died in that city and Washington.