Bolivia moved to reassure foreign investors on Friday, a day after its President Evo Morales set off alarm bells by saying foreign firms would not be compensated for nationalised oil and gas resources.
Bolivia will guarantee "genuine, long-lasting legal security" to foreign companies operating on its territory, Morales said in a letter sent to Spanish Foreign Minister Miguel Angel Moratinos on Thursday and made public Friday at a European Union-Latin America summit in Vienna.
EU leaders used the forum to urge Bolivia, as well as oil-rich Venezuela, to cooperate with foreign powers and keep trade ties active.
British Prime Minister Tony Blair called Morales and Venezuelan President Hugo Chavez to use their nations' petroleum resources "responsibly", according to his spokesman.
Blair "sent a double message" in letters to the two presidents although he did not meet them personally, spokesman Ian Gleeson said.
"He said they should use their energy resources responsibly, and that in their own economic interest... they should work with foreign investors," Gleeson said.
French President Jacques Chirac, meanwhile, has expressed "confidence" in discussions between Bolivia and foreign companies with interests in its energy reserves - which include the French oil group Total - a French government source said in Vienna.
Chirac expressed "his confidence in the discussions carried out in a spirit of dialogue and with willingness to respect the legitimate interests" of each party, the French delegation at the summit said.
"We hope that Bolivia will be sensitive to the interests of foreign co-operation," the source reported Chirac as saying.
Morales claimed a stunning victory when he won Bolivia's presidential election last December after pledging to take a bigger share of earnings from Bolivia's vast energy resources.
Foreign companies now have six months to renegotiate their contracts with Bolivia's state-run hydrocarbons company Yacimientos Petroliferos Fiscales Bolivianos (YPFB).
During the transition period, 82 percent of profits will go to the Bolivian state and 18 percent to the corporations.
EU and Latin American leaders warned in Vienna Friday that developing trade ties could be hit by populist moves by nations such as Bolivia and Venezuela to protect their energy sectors from foreign control.
The Vienna summit of 60 heads of state and government heard calls for more balanced trade relations, with a draft joint statement demanding a "more compatible regulatory regime."
The statement does not refer to Bolivia and Venezuela by name, but clearly has them in mind - as did some of the speakers at Friday's opening plenary session.
European Commission chief Jose Manuel Barroso called for a "convergence of interests, not only of values," and Austrian President Heinz Fischer said they should remain "convinced of the long-term economic benefits for the (member) states of greater strategic co-operation."
Mexican President Vicente Fox warned Latin America that populism "hinders meeting the challenges we have."
The leaders are to adopt a 16-page joint statement stressing human rights, the fights against terrorism, drugs and organised crime, and concern for the environment, "including disaster prevention," according to a draft.