* Guaido hit with travel ban, bank freeze
* Opposition plans more street protests
* Maduro thanks Russia for support, suggests talks
The fight for control of Venezuela intensified on Wednesday as the government pushed a probe that may lead to the arrest of opposition leader and self-declared interim president Juan Guaido who called for new street protests.
Venezuela's Supreme Court imposed a travel ban on Guaido and froze his bank accounts in apparent retaliation for oil sanctions imposed by the United States that are expected to severely hit the OPEC member's already collapsing economy.
Guaido is recognized as president by the United States and most Western Hemisphere nations, presenting the biggest challenge to President Nicolas Maduro's six-year rule.
The 35-year-old opposition lawmaker, who is president of the National Assembly, wants new elections, arguing that Maduro fraudulently won a second term last year. Guaido is offering an amnesty to tempt military officials to join him.
Maduro, who accuses Guaido of staging a US-directed coup against him, still has the support of the top military brass, and is unlikely to back down unless that changes.
Russia and China are also key benefactors, giving him backing at the UN Security Council.
On Wednesday, Maduro rejected calls for a snap presidential election as blackmail, and reiterated he was ready for talks with the opposition and possible third country mediation, Russia's RIA news agency reported.
"There are several governments, organizations globally, which are demonstrating their sincere concern about what is happening in Venezuela, they have called for a dialogue," RIA quoted Maduro as saying.
Given the failure of previous rounds of dialogue, including one led by the Vatican, opponents are suspicious, believing Maduro uses them to quell protests and buy time.
With the Venezuela crisis deepening a geopolitical showdown between Washington and Moscow across various global flashpoints, Maduro also expressed "pleasure and gratitude" for Putin's help.
Russia has loaned and invested billions of dollars in Venezuela, and sources told Reuters private military contractors who do secret missions for Moscow were in Venezuela.
A former union leader who succeeded his charismatic mentor, the late President Hugo Chavez, Maduro, 56, has overseen a shrinking economy and the migration of more than 3 million Venezuelans fleeing food and drug shortages and hyperinflation.
Guaido called for more protests on Wednesday and a mass march at the weekend, to keep up pressure on Maduro in the streets. Wednesday's action would not be a major march, but a series of small concentrations, he said.
More than 40 people have died so far in and around the protests that began a week ago, the UN human rights office said. Hundreds have also been arrested, including children.
Government supporters have also attended large rallies led by Maduro allies, while the president visited military bases including overseeing live-fire exercises in recent days.
He ordered the creation of 50,000 popular defense units, community groups he said would be charged with the "integral defense of the fatherland." While it was not clear if they would be armed, the strategy reflects government concern the United States could try to defeat Maduro militarily.
The Pentagon has refused to rule out military action, although is it not considered likely by most experts.
Trump's top advisers include Cold War-era hawks.
White House national security adviser John Bolton fueled speculation this week when reporters saw a notepad he was carrying had the words "5,000 troops to Colombia" written on it.
Colombia neighbors Venezuela.
US Vice President Mike Pence met Guaido's designated envoy to the United States on Tuesday. Pence said they discussed recent sanctions actions, "highlighting that these deprive Maduro and his cronies access to corrupt income and ... preserve the country's wealth for the people of Venezuela."
The sanctions are also likely to hit daily life hard in Venezuela, where public spending is almost entirely funded by oil revenues. The government is eager to blame Guaido for the measures, which, once they begin to bite, could diminish his popularity.
Venezuelan Attorney General Tarek Saab sought the preliminary investigation of Guaido on the basis that he had helped foreign countries interfere in internal matters.
Announcing the investigation, the travel ban and the financial restrictions, Supreme Court President Maikel Moreno, a major Maduro ally, said the decision was taken expressly to "protect the integrity of the country." In a tweet, Bolton warned of "serious consequences for those who attempt to subvert democracy and harm Guaido."