Caracas, Venezuela (CNN) -- While many world leaders have condemned Syrian President Bashar al-Assad, the embattled leader has found an ally in Venezuelan President Hugo Chavez.
The South American country's state-run oil company has sent large diesel shipments to Syria, despite international sanctions.
In recent months, Venezuela supplied Syria with at least three shipments of diesel fuel in exchange for Syrian naphtha, a refined petroleum product, according to a May report from the U.S. Congressional Research Service.
In late May, Syria's oil minister said that an oil tanker loaded with 35,000 tons of diesel fuel had arrived in his country from Venezuela, the state-run Syrian Arab News Agency reported. At the time, he said Venezuela was preparing another tanker to head to Syria.
Citing Venezuelan and Syrian government documents, the Wall Street Journal reported this week that a fourth shipment was in the works. CNN has not independently confirmed that report.
Chavez and the president of Venezuela's state-run oil company have defended their sovereign right to send fuel to Syria.
"If they need diesel, and we can provide it, there is no reason not to do it," Rafael Ramirez, Venezuela's energy minister, told reporters in February, according to state media reports.
Ramirez, who also heads the state-run oil company, said Venezuela was not worried about possibly facing international sanctions for sending fuel to the Middle Eastern nation.
"We cannot determine our foreign policy with fear of U.S. sanctions," he said. "We have said that those truly don't matter to us."
Chavez and al-Assad have a "longstanding personal fraternity," Venezuela's foreign ministry said in a statement after the two leaders spoke on the phone in April.
This week, Chavez criticized what he said was Washington's imperialistic approach to Syria.
"They should be focusing on solving their own country's problems, but they want to impose themselves, like they did in Libya, where they killed thousands and thousands of people to then kill (Libyan leader) Moammar Gadhafi, and now they want to do the same with Syria and they are also threatening Iran," he said, according to state-run VTV.
In March, Venezuela's parliament passed "an agreement in solidarity with Syria in light of the imperial threat presented by the United States and its Arab allies."
"The document exhorts the international community and peace lovers to undertake a massive campaign to reject intervention in that nation," Venezuela's interior ministry said.
Critics have alleged that fuel sent by Venezuela has been used to maintain the Syrian government's military operations.
Otto Reich, a U.S. assistant secretary of state during President George W. Bush's administration and a fierce critic of Chavez, told Venezuela's El Universal newspaper last month that he feared ships sending fuel could have a more nefarious purpose.
"Chavez uses his own vessels because no self-respecting international shipping firm will transport fuel to Assad's killing machine. There is another advantage, however: since he controls the entire voyage, from dock to dock, Chavez may be sending Assad military material hidden in the ships," he said.
Alberto Aranguibel, a political analyst in Caracas who supports Chavez, told CNN en Español Tuesday that the fuel shipments are an economic and humanitarian matter.
U.S. sanctions against Syria must be stopped, he said.
"There is a humanitarian reason. The blockade is arbitrary, illegal and illegitimate. ... It doesn't affect the government. It affects the people," he said.
Mauricio Meschoulam, an international relations professor in Mexico City, told CNN en Español that Venezuela was one of many nations that had become involved in the Syrian crisis.
"They are, unfortunately, feeding the parties that are clashing," he said.
U.S. sanctions in Syria and Venezuela's attempts to defy them are part of a global geopolitical battle, he said.
"There are no good or evil (countries). They are all fighting for resources, each one searching for its piece of the pie," he said.
The close relationship between Venezuela and Syria has been years in the making.
After signing several agreements with al-Assad on an October 2010 trip to Syria, Chavez said the country's capitals "have become the poles of the new world."
"We are obligated to weave the connections between Damascus and Caracas with threads of steel ... new economic, political, agricultural and scientific relations much strengthen so we can overcome together the great challenges that the times we live in impose," Chavez said.
Violence erupted in Syria in March 2011, when Syrian forces launched a brutal crackdown on anti-government demonstrations, part of the Arab Spring that swept through several countries. Syrian officials have regularly blamed "armed terrorist groups" for the clashes.
The United Nations says more than 10,000 people, mostly civilians, have been killed in the violence. Opposition groups give an even higher figure.
CNN cannot independently confirm reports of violence in Syria, as the country's government has severely limited the access of international journalists.
CNN's Catherine E. Shoichet, CNN en Español's Fernando del Rincon and journalist Osmary Hernandez contributed to this report.