Kabul, Feb 14 : At least 20 people were injured in a fire that broke out at the customs office of the Islam Qala dry port in Afghanistan, the media reported on Sunday. "More than 1,000 oil, gas and cargo trucks were destroyed by Islam Qala port fire in Herat province that broke out Saturday afternoon and put out late Saturday night," Xinhua news agency quoted a Tolo News report as saying. Local officials was quoted in the report as saying that the fire had caused a direct economic loss of over $50 million in the port that connects Afghanistan with Iran. Iran has provided help in response to a request from Afghanistan's authorities. Jilani Farhad, provincial government spokesman, told Xinhua that an armed clash between militants and security forces took place in Islam Qala on Saturday. However, Farhad did not say whether the incident was a terrorist act, saying that investigation could determine the reason. "A probe is still on," he added. /IANS