The U.S. Department of Justice has decided to conduct further deliberations over the planned merger of South Korea's Korean Air and Asiana Airlines.

According to Korean Air on Wednesday, the U.S. department said it plans to continue reviewing the proposed merger beyond the 75-day deliberation period initially agreed upon with the Korean flag carrier.

The extension will afford U.S. authorities more time to thoroughly determine whether the merger could result in a market monopoly due to the two airlines’ large number of North America-bound routes, with such flights accounting for 29 percent of Korean Air's sales prior to the COVID-19 pandemic.

With the authorities expected to focus on the merger’s effect on market competition, Korean Air reportedly said that competition will not be restricted if domestic carrier Air Premia and U.S. companies United Airlines and Delta Air Lines expand their routes between the two countries.

The U.S.’ decision comes after Britain's Competition and Markets Authority(CMA) raised concerns on Monday over the planned merger, citing a possible market monopoly potentially resulting in higher prices for passengers flying between London and Seoul.