MEXICO CITY (AP) _ NBC is suing a Mexican bank for $300 million, alleging breach of contract in relation to the network's dissolved alliance with Mexico's TV Azteca.

Banca Serfin was appointed by NBC as its trustee to hold stock warrants and payments in transactions between NBC and the Mexican network.

The suit, filed Monday in a Mexican court, alleges Serfin failed to uphold NBC's contractual rights when the network tried to exercise warrants to buy Azteca stock. The suit says the bank first consulted with Azteca before making a decision regarding NBC's rights.

The suit also alleges Serfin has at least two business relationships with Azteca that cause a potential conflict-of-interest with its role as NBC's trustee.

Serfin officials were unavailable for comment Tuesday.

In April, NBC and Azteca announced that their three-year-old alliance dissolved, with both networks blaming each other for the breakdown.

The companies agreed to a deal in 1994, soon after formerly state-owned Azteca was privatized, for NBC to provide management and programming expertise in exchange for $7 million and a chance to expand the U.S. network's identity abroad.

NBC, owned by General Electric Co., said Azteca broke their contract by refusing to honor an option NBC wanted to exercise to buy 1 percent of Azteca shares. The deal gave NBC options to acquire up to 10 percent of Azteca.