Venezuelan President Hugo Chavez, who is on a four-nation Latin American tour, signed on Wednesday an energy security pact with his Uruguayan counterpart Tabare Vazquez.

Under the agreement, Venezuela pledges to supply Uruguay with oil and gas for 100 years and help build an insulin factory in Uruguay, which will sell its products across Latin America.

Both countries' state oil companies -- Uruguay's Ancap and Venezuela's PDVSA -- will work together to expand Uruguay's oil refinery in Montevideo.

In addition, PDVSA has agreed to buy 10 percent of Uruguay's state sugar mill.

At a press conference after meeting with Vazquez, Chavez reiterated Venezuela's aspiration to join the Common Market of the South (Mercosur).

Venezuela signed an agreement to join Mercosur over a year ago, but its entry has not been ratified by lawmakers in Brazil and Paraguay.

Vazquez restated his support for Venezuela's full membership of Mercosur. Uruguay holds the six-month rotating presidency of the body until the end of 2007.

Rejecting speculations by some political analysts that Venezuela and Uruguay are drifting apart, the two presidents said their relations were excellent.

"There is no room for doubt. Uruguay's people have to, as I the nation's president will now, express their deepest gratitude to this government, which has been a brother and friend to Uruguay," Vazquez said.

He said Uruguay would like to help Venezuela develop its agricultural and software industries.

Chavez started his four-nation tour in South America on Monday in efforts to boost influence and promote Venezuela's entry into the Mercosur trade bloc. He has visited Argentina and will travel to Bolivia and Ecuador.