BRUSSELS (AP) — U.S. Secretary of State John Kerry has brought senior Afghan and Pakistani officials together for security talks aimed at improving relations between the two nations ahead of next year's withdrawal of NATO combat forces from Afghanistan.

Kerry was meeting Afghan President Hamid Karzai and Pakistani military chief Gen. Ashfaq Parvez Kayani on Wednesday at Truman Hall, the secluded estate on the outskirts of Brussels that is home to the U.S. Ambassador to NATO. Kerry said as he opened the meeting that the talks were important, as Afghanistan is currently in a "critical transformational period."

Ties between Afghanistan and Pakistan have long been strained over links between Pakistan's security apparatus and the Taliban. The U.S. supports Afghan-Taliban reconciliation but Karzai has said the effort must have Pakistan's backing to succeed.