HAVANA, Feb. 25 � Cuba made good early today on its threat to suspend most telephone links with the United States in retaliation for the withholding by five American telecommunications firms of $19 million in payments owed to the state-controlled phone company here.

At 12:01 this morning, the Telecommunications Company of Cuba S.A. (ETECSA) � a joint venture with an Italian partner in which the government has a majority stake � cut off more than 80 percent of its phone ties with with the United States after a its deadline for payment passed.