Russian Federation says it is concerned that the U.S.is considering military intervention in Venezuela.
U.S. State Department spokesman Robert Palladino says Pompeo called Foreign Minister Sergei Lavrov on Monday and said "the United States and regional countries will not stand idly by" while Russian Federation takes steps to support its ally, Venezuelan President Nicolas Maduro.
US Secretary of State Mike Pompeo, while reacting to the situation with Russian visit, said Monday that "the United States and regional countries will not stand idly by as Russia exacerbates tensions in Venezuela".
Pompeo said "the continued insertion of Russian military personnel" in Venezuela could prolong the country's problems and urged Russia "to cease its unconstructive behavior".
Marrero, a 49-year-old lawyer, was arrested on Thursday in his Caracas home, triggering an outcry and demands that he be immediately released by the United States, the European Union and major Latin American countries that recognize Guaido as Venezuela's interim president.
Pompeo encouraged Russian Federation over the phone call to stand with the United States in supporting opposition leader Juan Guaido.
The planes arrived in the Venezuelan capital on Saturday.
Maduro accuses US of financing mercenary 'plot' against him
He showed screen grabs of cell phone conversations that he said are proof Marrero was orchestrating the hitmen's payment. Guaido characterized the operation as a sign that Maduro is losing his grip on power.
U.S. President Donald Trump said in 2017 that the "military option" was on the table when it comes to Venezuela, but administration officials have since downplayed talk of armed intervention.
An Ilyushin IL-62 passenger jet and an Antonov AN-124 military cargo plane left for Caracas on Friday from Russian military airport Chkalovsky, stopping along the way in Syria, according to flight-tracking website Flightradar24.
The statement said such moves "constitute violations of the United Nations charter and undisguised interference in the internal affairs of a sovereign state".
Bloomberg News, citing an unnamed Venezuelan information ministry official, reported that the officials had come to perform maintenance on Russian military equipment that Venezuela had purchased through bilateral accords.
In a show of solidarity in December, Russian and Venezuelan forces conducted a joint military exercise in the South American country.
By putting its troops on the ground in Venezuela, Russia is sending a clear message to Washington that the Latin American country is under the Kremlin's protection.
Russian Federation and China are the main allies of Venezuela. Electricity experts and opposition leader Juan Guaido faults years of government graft and incompetence.
The escalation raises the likelihood of a standoff between Russian Federation and the USA for influence in the strategically significant Latin American power as rumors continue to circulate the Trump administration may escalate its direct involvement there.