BARCELONA, Apr 27 (Reuters) - Cellnex said on Wednesday it has given a board seat to activist fund TCI, the Spanish cell phone tower operator's largest shareholder, which has put pressure on the company's top management, prompting the resignation of two independent directors this month.

Internal turbulence has hit Europe's largest mobile tower operator after TCI in March sought to oust its chairman and two board members, claiming it mismanaged the search for a new CEO, resulting in insufficient progress.

TCI requested in March that its representative Jonathan Amouyal join Cellnex's board, which was approved on Wednesday, a day before it announced its first-quarter results.

The board also approved appointing María Teresa Ballester as an independent director, Cellnex said in a statement.

Both appointments will have to be ratified at an upcoming general shareholders' meeting.

A week after being replaced as non-executive chairman, Bertrand Boudewijn Kan resigned as a member of Cellnex's board on April 4, along with fellow director Leonard Peter Shore, citing "irreconcilable differences" with the board regarding the company's management, governance and succession process.

TCI had sought her departure, but has not met its other objective of ousting Alexandra Reich, who represents Singapore sovereign wealth fund GIC Private Limited and sits on the nominating committee, according to Spanish stock regulator records.

TCI became Cellnex's largest shareholder in March with a 9% stake, including 5.9% in derivatives, overtaking Italian group Edizione.

Barcelona-based Cellnex announced in January that its CEO, Tobias Martinez, will step down in June after initiating a change in strategy, moving away from intense acquisition activity to focus on reducing its debt.

(Reporting by Joan Faus; editing by Aislinn Laing and Josie Kao; edited in Spanish by Dario Fernandez)