Mumbai: Reliance Communications has extended the period of its exclusive talks with South African telecom major MTN till 21 July, the company said in release.

The company did not say anything about the status of talks aimed at a "potential business combination.'' The release also did not detail the status of Reliance Communication's talks with Reliance Industries.

''RCOM and MTN have agreed to continue their negotiations in relation to such potential business combination, and have extended the period of exclusivity until July 21," Reliance Communications said in the statement.

"It is to be noted that there is no certainty either on completion, or the timing of the said proposal," the statement added.

In separate regulatory filings, the two companies also cautioned their respective shareholders on dealing in the scrips amidst the ongoing talks.

The two companies started negotiations for a 45-day exclusivity period on 26 May, which ended on July 8.

A merger of MTN and Reliance Communications is estimated to be worth up to $70 billion (SA Rand 537.6 billion), but it is uncertain whether the talks will end in a deal.

"There is no certainty either on completion, or the timing of the said proposal," the statement added.

Meanwhile, the Ambani brothers have so far failed to sort out differences over the proposed alliance with MTN.

Officials of Reliance Communications and Reliance Industries had agreed to meet and discuss any ''doubts'' RIL may have, and ''not to pave a way for any reconciliation.'' But that too hasn't materialised until 8 July when MTN and Reliance Communications were to conclude their exclusive negotiations.