Afghanistan on Wednesday expressed disappointment at Pakistan President Pervez Musharraf's decision not to attend what it called a "historic" meeting to address the rising Taliban threat.
Musharraf pulled out of the "peace jirga", bringing together elders from troubled tribal areas on the rugged common border to discuss anti-terror strategies, because of "engagements in the capital," his foreign ministry said.
Afghanistan said it would welcome Pakistan's Prime Minister Shaukat Aziz in his place at the three-day meeting set to begin Thursday.
But the office of Afghan President Hamid Karzai said Musharraf has agreed to attend when the meeting was proposed at a three-way summit with US President George W. Bush last year.
"Based on agreements made earlier, we expected President Musharraf in Kabul to attend and address the representatives of Afghanistan and Pakistan at this important and historic event," Karzai's spokesman Homayun Hamidzada told AFP.
Karzai had emphasised the importance of Musharraf's "personal attendance in the jirga," during their phone conversation, he said -- suggesting the Afghan leader had tried to convince his Pakistani counterpart to change his mind.
Nonetheless, Afghanistan is "doing everything we can to bring peace, stability and prosperity to both Afghanistan and Pakistan," the spokesman added.
The Afghan foreign ministry said Musharraf's failure to attend would have "no effect" on the meeting, which will bring hundreds of delegates from the two countries to Kabul.
US State Department spokesman Sean McCormack indicated that the Pakistani military ruler could be persuaded to reconsider, saying: "We'll see if President Musharraf is able to attend some portion of the meeting."
The "peace jirga" -- modelled on a traditional tribal gathering called in times of crisis -- is the first among the two nations and comes with both increasingly under attack from Taliban militants and their Al-Qaeda allies.
It is being held in a massive white tent at a polytechnic in the west of Kabul where Afghanistan held its last jirga -- the 2003 meeting that drew up the country's first post-Taliban constitution.
The hardline militia has called for a boycott and tribal leaders from two of Pakistan's most Taliban-influenced tribal areas -- North and South Waziristan said they would not attend.
Security in the heavily barricaded city was even tighter ahead of the assembly.
Nearly 2,500 police had been deployed in Kabul for a week to secure the location of the jirga and delegates' accommodation, interior ministry spokesman Zemarai Bashary told reporters.
Key streets in the scruffy capital were decked out with the national flags of Pakistan and Afghanistan as well as ones made up especially for the jirga showing two hands shaking and doves of peace.
Relations between Karzai and Musharraf are already frosty over the Taliban, which was driven from government by a US-led coalition in 2001 after having being helped to government by Pakistan in 1996.
Pakistan is now an ally in the US-led "war on terror" but Afghan and Western officials have accused it of not doing enough to crack down on Taliban and Al-Qaeda sanctuaries in its tribal areas, a charge Pakistan denies.
The violence has meanwhile mounted steadily, with regular Taliban suicide bombings, roadside blasts and other deadly attacks on both side of the border -- some in the heart of Kabul and Islamabad.
"At this particular time when both countries are facing such insecurity challenges, it would be disappointing that the leaders of the two countries could not sit together at this vital peace initiative," a Western diplomat said in Kabul after Musharraf's announcement.
Faheem Dashty, the chief editor for the leading newspaper Kabul Weekly, said the political turmoil in Pakistan made Musharraf's absence from his country "dangerous".
"If this jirga is going to have any results, I think Mr. Aziz's presence will fill the absence of Musharraf," he added.