Afghanistan, Iran and Pakistan have agreed to jointly fight terrorism.
A statement by the three neighbouring presidents at a counter-terrorism summit follows an announcement by United States President Barack Obama that Washington will withdraw one third of its 99,000 troops from Afghanistan within 15 months.
The statement says all sides have stressed their commitment to efforts aimed at eliminating extremism, militancy and terrorism.
It also says the countries are committed to rejecting foreign interference.
Afghan President Hamid Karzai said that despite his government's efforts, regional militancy was rising.
"Unfortunately, despite all the achievements in the fields of education, infrastructure and reconstruction, not only has Afghanistan not yet achieved peace and security, but terrorism is expanding and threatening more than ever Afghanistan and the region," he said.
Pakistan's president Asif Ali Zardari said terrorism had cost 35,000 lives in Pakistan, 5000 of them law enforcement personnel, and caused material damage totalling $67 billion.
"Terrorists violate both human and divine values by inflicting death and destruction on fellow human beings. They have no religion," he said.
In his speech, Iran's President Mahmoud Ahmadinejad again accused Iran's arch-foe the United States of using the September 11, 2001 attacks as a "pretext" to send troops to the region.
"In light of the way it was approached and exploited, September 11 is very much like the Holocaust," he charged.
"The American government used the attacks as a pretext to occupy two countries, and kill, injure and displace people in the region", he said.
Mr Ahmadinejad has repeatedly courted controversy by questioning the accepted version of both the September 11 attacks, which killed nearly 3000 people, and the Holocaust during which six million Jews were killed.