A photo of V from BTS appears on a curved digital signage display at a hotel in Busan, Tuesday, three days before the idol group's concert in the southeastern port city. YonhapThe Incheon Airport Immigration Office is on high alert over an anticipated surge in international arrivals ahead of the upcoming BTS concert in the nation’s southeastern port city of Busan.The two-day concert, which kicks off Friday, will attract a huge number of foreign tourists, so the organization has expanded the number of immigration officers on duty for four days starting Wednesday. The immigration office is in charge of overseeing the entry and departure of foreigners at Incheon International Airport.According to data from the authority, the number of foreigners entering through the airport on Thursday is estimated to reach around 48,660, up 15 percent from the previous week.The office plans to deploy additional supervisory and guidance staff throughout inspection halls around the airport and conduct advance monitoring of foreign passenger arrivals by flight to reduce crowding and improve passenger flow.“We remain highly vigilant over the possible influx of foreign tourists and are making concerted efforts to minimize waiting times at immigration checkpoints,” an official from the authority said.Foreign arrivals rose sharply during the previous BTS concerts here in April. The number of foreign nationals entering the country through the airport soared 26 percent over that period, compared with the daily average of 38,000 foreign arrivals recorded in May.By nationals, Chinese tourists accounted for the largest share, while the number of travelers from Japan, Taiwan and several Southeast Asian countries also increased significantly in the lead-up to the concert. “We will expand the number of immigration officers on duty by up to 88 percent during the four days,” the official said.Even though some foreign tourists will arrive in Korea via Gimhae International Airport in Busan, a considerable number are expected to enter through Incheon International Airport due to its greater capacity.