MADRID, March 8 (Reuters) - Spanish regional telecom operator Euskaltel will spin off its broadband infrastructure unit and sell a minority stake by the end of the second quarter, its CEO said in an interview on Monday.

Through the operation, the group is seeking to free up cash to boost its retail mobile phone business beyond its regional base in northern Spain and sell wholesale broadband services to rival operators developing 5G networks, Chief Executive Jose Miguel Garcia told Reuters.

"I believe we can complete this operation in the second quarter," he said, though he declined to give details about the size of the deal. (Reporting by Inti Landauro; editing by James Mackenzie)