The outspoken Venezuelan leader lashed out after William Brownfield said U.S. companies and investors must receive a fair price for their shares of Venezuela's largest telephone company when Chavez's government nationalizes it.
"If you continue meddling in Venezuela's affairs, first of all, you are violating the Geneva agreements and getting yourself involved in a serious violation and could ... be declared a persona non grata and would have to leave the country," Chavez.
The top American envoy to Venezuela told Caracas' Union Radio the planned takeover of CA Nacional de Telefonos, or CANTV, should proceed "in a transparent, legal manner" and that Venezuela's government must offer "fair and quick compensation to the people who are affected or the owners."
"These are the only obligations that a government has when it decides to nationalize an industry," Brownfield added.
Thursday's exchange is the latest demonstration of tensions between Caracas and Washington.
U.S. officials have accused Chavez of becoming increasingly authoritarian and of being a destabilizing force in Latin America. The Venezuelan leader has repeatedly accused Washington of scheming against his left-leaning government.
Virginia-based Verizon Communications Inc. holds the largest minority share of CANTV, which was privatized in 1991. The takeover jeopardizes an agreement by Verizon to sell its 28.5 percent stake in CANTV to a joint venture of America Movil and Telefonos de Mexico SA, controlled by Mexican billionaire Carlos Slim.
The sale had been awaiting Venezuelan government regulatory approval.
Chavez, a self-proclaimed "revolutionary" who is steering Venezuela toward socialism, has said he wants an immediate state takeover of the telephone company and will not pay shareholders the market value. The Venezuelan leader has said the price for CANTV would take into account debts to workers, pensions and other obligations to the state.
Brownfield said he was optimistic that shareholders would be fairly compensated.
"I think it can be a process that concludes in a satisfactory manner for all those involved, that's my hope," he said.
Chavez _ a close ally of Cuban leader Fidel Castro also has said he plans to nationalize the electricity sector, and take state control of four lucrative oil projects and the natural gas sector.
Relations between Caracas and Washington have been tense since Chavez was briefly ousted in a 2002 coup that he claimed the U.S. played a role in. The Bush administration has repeatedly denied involvement, although it recognized an interim government established by coup leaders.
Brownfield said he wanted to improve relations through "a serious and pragmatic dialogue between the two governments, to identify issues of mutual interest and to look for solutions to those issues."