WASHINGTON (Agencies) The Obama administration says Pakistan is considering pulling out of an international conference on Afghanistan next week as a result of the NATO airstrikes that killed 24 Pakistani soldiers. State Department spokesman Mark Toner says Pakistani officials have informed the US they are reviewing their participation. He acknowledged that the weekend incident was a setback for US-Pakistani relations. The conference next week in Bonn, Germany, seeks a strategy to stabilize Afghanistan a decade after al-Qaida used the country as a base to launch the 9/11 attacks and U.S.-backed forces overthrew the Taliban. Toner urged Pakistan to attend. He also said Monday that investigations were under way into the NATO strikes. He said Washington and Islamabad will have to work through the difficulties in their vitally important relationship. Maqbool Malik from Islamabad adds: Pakistan has stepped up diplomatic efforts to seek written agreements with the United States as well as NATO/ISAF for future cooperation in the war against terror, sources said on Monday. Following the NATO attack, Pakistan will not cooperate with the US and NATO until and unless they sign written agreements on new rules of engagements for cooperation in the war against terror, a senior government official told The Nation. The sources requesting not to be named said that Pakistan was also engaged in weighing options as to whether it should participate or boycott the international conference on Afghanistan to be held in Bonn, Germany, from December 5-8.