British Prime Minister Theresa May said her government was trying its best to look into reports of a missing child with dual British nationality after deadly terrorist attacks in Spain which left 14 people dead."We're urgently looking into reports of a child believed missing, who is a British dual national," Xinhua news agency quoted the Prime Minister as saying."Sadly, I must tell you that we do believe that a number of British nationals were caught up in the attack," she said.The seven-year-old boy, Julian Alessandro Cadman, was separated from his mother when a van rammed into a crowd of people in the pedestrian area in central Barcelona on Thursday, reports said, citing a post on social media from the boy's grandfather.Cadman's mother was badly injured and is reportedly in a serious condition in hospital. The family has shared a picture of Cadman in a bid to find the boy from Australia. "The Foreign Office is offering consular assistance to those who were involved in the attack and their families, and are working urgently to see if there are others who need their help," May said.Earlier Friday, May spoke with Spanish Prime Minister Maiano Rajoy over the double terror attacks. "Terrorism is the great threat we all face," she said.Thirteen people were killed Thursday afternoon in the popular Las Ramblas area of Barcelona when a white van zigzagged at high speed down the busy avenue thronged with tourists, knocking down pedestrians.