Reliance Communications , India's second-biggest mobile phone carrier by subscribers, continues to be in talks with potential investors to sell its telecoms tower unit, but a transaction will proceed when there is clarity on airwave rules, a senior company executive said on Monday.

Punit Garg, president at Reliance Communications, did not name any of the potential investors in a conference call with analysts after the company reported its fourth-quarter earnings.

Reliance Communications, controlled by billionaire Anil Ambani, has long been trying raise funds by selling assets to cut its debt load - $7 billion as of March - but had little success so far.

The company has been in talks with U.S. buyout firms Blackstone and Carlyle for the last several months, sources have said, but a deal is yet to be sealed.

(Reporting by Devidutta Tripathy in NEW DELHI; editing by Malini Menon)