Two Russian strategic bombers landed in Venezuela on Monday.

Their arrival comes amid increased tensions between the US and Russia, and during a US-led pressure campaign on Venezuela.

Russia remains one of Venezuela's most important allies, but there are limits to its support.

Two Russian Tu-160 nuclear-capable strategic bombers arrived in Venezuela on Monday, and their presence has already prompted dueling statements from Washington and Moscow.

The bombers landed at Maiquetia Airport outside Caracas after a 6,200-mile flight, the Russian Defense Ministry said. They were accompanied by an An-124 military transport plane and an Il-62 long-range aircraft.

The Defense Ministry said the journey took the bombers through the Arctic and Atlantic oceans, but the flight was "in strict compliance with international rules of the use of airspace."

Moscow didn't say if the bombers carried weapons, but they are capable of carrying conventional or nuclear-armed missiles with a range of 3,400 miles.

Venezuelan President Nicolas Maduro, center, next to Defense Minister Vladimir Padrino Lopez, right. Miraflores Palace/Handout via REUTERS

Venezuelan Defense Minister Vladimir Padrino Lopez has said the Russian aircraft would conduct joint flights with Venezuelan planes. Moscow hasn't said how long this trip would last, but it has already drawn a response from the US, which views Venezuela as its most significant foe in the region.

"Russia's government has sent bombers halfway around the world to Venezuela," Secretary of State Mike Pompeo said on Twitter. "The Russian and Venezuelan people should see this for what it is: two corrupt governments squandering public funds, and squelching liberty and freedom while their people suffer."

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The Pentagon also criticized the deployment, contrasting it with the US dispatching the hospital ship USNS Mercy, which treated tens of thousands of patients, many of them Venezuelans, on a tour of South America this year.

"As the Venezuelan government seeks Russian warplanes, the United States works alongside regional partners and international organizations to provide humanitarian aid to Venezuelans fleeing their crisis-racked nation," Pentagon spokesman Eric Pahon said Monday. "We maintain our unwavering commitment to humanity."

Colombian and Venezuelan patients rest after surgery in the hospital ship USNS Comfort on November 27, 2018. Fernando Vergara/Associated Press

The Kremlin rebuked Pompeo, with Russian presidential spokesman Dmitry Peskov telling reporters that Pompeo's comments were "rather undiplomatic" and that Moscow "consider[s] this statement to be totally inappropriate."

He also chided the US for labeling the deployment as a waste of money. "It is not appropriate for a country half of whose defense expenditure would be enough to feed all of Africa's people to make such statements," Peskov said.

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Russia's Foreign Ministry also joined the fray. In a statement released Tuesday, the ministry said it acknowledged that "tweets" did not "bind anyone to anything in the US in general."

"However in this situation an official is involved, so this disregard of the rules of diplomatic ethics cannot be seen as a statement 'to dismiss,'" the ministry added. "What the secretary of state said is inadmissible, not to mention that it is absolutely unprofessional."

Good friends, but not best friends

Russia's President Vladimir Putin, left, shakes hands with Venezuelan President Nicolas Maduro. AP Photo/RIA Novosti, Alexei Nikolsky, Presidential Press Service

Tu-160 bombers last visited Venezuela in 2013 and 2008, the latter trip coming during heightened tensions over Russia's war with Georgia. Tensions between Washington and Moscow are again heightened, amid Russia's intervention in Ukraine and meddling in the 2016 US presidential election, but Moscow's ties to Caracas are longstanding.

"In the Chávez era, Russia was a major arms supplier to Venezuela, and Russia’s state-owned oil company, Rosneft, remains a major player in Venezuela’s collapsing oil sector," Benjamin Gedan, former South America director on the National Security Council and a fellow at the Wilson Center, said in an email.

"In recent years, as once prosperous Venezuela became an international panhandler, Russia renegotiated loans to postpone sovereign default," Gedan added.

Russia remains one of the most important international allies for the increasingly isolated regime of Venezuelan President Nicolas Maduro, Gedan said, but that support is not as robust as it may appear.

People walk past graffiti that reads: "Maduro, misery" in Caracas, Venezuela, August 18, 2018. REUTERS/Marco Bello

Russia's own oil industry has faced headwinds, and its economy has been strained by sanctions imposed by the US and European Union after its 2014 annexation of Crimea. While Russian President Vladimir Putin remains broadly popular, backlash to a government plan to raise pension ages has dented his standing.

"Russia's generosity is motivated in part by its desire to prop up a Latin American regime that is hostile to US interests," Gedan said. "That said, Moscow does not have the wherewithal to bail out Venezuela. Given the impacts of sanctions and relatively low oil prices, Russian support for Venezuela these days mostly involves purchases of oil assets priced to sell by the desperate Venezuelan government."

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Maduro returned from a three-day visit to Russia last week touting $6 billion in investments, including a $5 billion pledge for joint oil ventures and a Russian agreement to send 600,000 metric tons of wheat to Venezuela in 2019.

But officials in Russia questioned those deals, with one Rosneft official telling the Financial Times that the amount of new oil investments mentioned by Maduro sounded "suspiciously close" to the amount of the existing agreement.