The trade between Tehran and Kabul stands at $4 billion, the deputy foreign minister for consular, parliamentary and Iranian expatriates affairs, Hassan Qashqavi, said on Saturday. As IRNA reported, the senior foreign ministry official made the remarks in a meeting with senior local university officials of South Khorasan Province. He said that the province, with over 460 kilometers of joint borderline with Afghanistan, can play a pivotal role in enhancing the level of trade between Tehran and Kabul.