LIMA: US National Security Adviser John Bolton on Monday warned China and Russia not to double down in support of Venezuelan President Nicolas Maduro, saying Venezuela might not repay its debt to them after Maduro falls.

Bolton said a democratically elected government in Venezuela may view the two countries as hostile powers for supporting what he called the "criminal regime" of Maduro for so long, and could opt not to pay them back billions of dollars in loans.

Ongoing support for Maduro "could affect repayment of their debt after Maduro falls," Bolton told journalists in Peru on the eve of a summit there on Venezuela's political crisis.

Bolton said he would give a speech at the summit that outlines a new US initiative to find a peaceful transfer of power in Venezuela. Russia and China turned down invitations from Peru to attend the gathering of more than 50 countries.

The United States, most Latin American countries and most Western democracies have called for Maduro to step down, recognizing Venezuelan opposition leader Juan Guaido as the country's rightful president.

In January, Guaido invoked the constitution to assume an interim presidency, arguing Maduro's 2018 re-election was illegitimate.

Russia and China continue to back Maduro, who has called Guaido a puppet of the United States and retains control of most institutions.

Guaido and his allies have repeatedly argued that China and Russia are more likely to collect on their loans to Venezuela with Maduro out of office. However, the opposition has criticized some Russian loans because they were not approved by the National Assembly.

Bolton added that Washington is opposed to new elections in Venezuela while Maduro remains in power because his government could manipulate the electoral system in his favor.

He called ongoing talks between Maduro's government and the opposition in Barbados "not serious" and said the longer they go on, the more advantageous they are for Maduro.