A Turkish government official says the leaders of Pakistan and Afghanistan will meet in Istanbul to improve ties and boost cooperation. Afghanistan often accuses neighboring Pakistan of failing to take action against - or even colluding with - Taliban militants. But more recently, Afghan President Hamid Karzai and Pakistan's new President Asif Ali Zardari have forged a closer personal relationship. A government official said the two leaders will meet in Istanbul on Friday. He spoke on condition of anonymity because he was not authorized to speak to journalists.