Pakistan is dismissing international calls to reconsider its boycott of next week's international conference on Afghanistan.

The government decided not to attend the December 5 summit in Bonn in protest of Saturday's deadly NATO air assault that killed 24 Pakistani soldiers at military posts near the Afghan border.

Pakistani Prime Minister Yousuf Raza Gilani briefed reporters Wednesday on a phone conversation with Afghan President Hamid Karzai , who asked him to reconsider the decision not to attend the conference.

Prime Minister Gilani said he told President Karzai that Pakistan can not play a constructive role in the Afghan peace process until its own sovereignty, security and integrity are ensured. The Pakistani leader said he told President Karzai to talk to the United States about Afghan territory being used against Pakistan.

The Pakistani government responded to the NATO attack by shutting down NATO's Pakistani supply routes into Afghanistan and ordering U.S. personnel to evacuate an air base in Baluchistan province within two weeks.

On Wednesday, U.S. Secretary of State Hillary Clinton said Washington and Islamabad should learn lessons from the incident so the two countries can continue fighting terrorism together. She pledged a quick and thorough investigation of what she called a “tragic incident.”

Clinton also said she regrets Pakistan's withdrawal from next week's international conference on Afghanistan but hopes to secure Islamabad's cooperation in the future.

Clinton told a news conference in South Korea Wednesday that Pakistan, like the U.S., has a “profound interest in a secure, stable and increasingly democratic Afghanistan.”

Pakistani General Ashfaq Nadeem said Tuesday that the NATO assault was a “deliberate act of aggression.” He also questioned whether Pakistan would participate in Washington's investigation into the air assault.

The U.S. military has until December 23 to submit the findings of its investigation. NATO has also launched a probe.

The Associated Press quotes U.S. officials as saying investigators believe the Taliban attacked a U.S.-Afghan patrol in the border region to create confusion and draw U.S. and Pakistani forces into firing on each other.

The Bonn conference is aimed at developing a strategy to stabilize Afghanistan as coalition forces withdraw in the coming years. Many analysts agree that peace in Afghanistan hinges on whether Pakistan plays a constructive role in the process.

The White House calls the Bonn talks very important for the future of Afghanistan and says Pakistan will play a very important role.