Venezuelan President Nicolas Maduro arrived in Tehran Friday for a 24-hour visit during which he will meet officials from fellow OPEC member Iran to discuss plunging oil prices, state television said.

Crude oil prices, which have been sliding for months, hit a five and a half year low this week. That has resulted in severe financial headaches for members of the Organization of Petroleum Exporting Countries.

Gunmen opened fire during a burial at a Venezuelan cemetery on Thursday, leaving seven people dead and five wounded, authorities said.

The shooting took place in the old graveyard of the central town of Turmero, the attorney general's office said in a statement.

China and Venezuela will step up co-operation this year, Presidents Xi Jinping and Nicolas Maduro said in Beijing Wednesday as falling oil prices threaten the Latin American nation's economy.

Maduro was widely expected to ask for a new cash injection to shore up oil-rich Venezuela's finances during his visit as elections loom and a faltering economy could hurt his left-wing party's chances.

Venezuelan President Nicolas Maduro called for "respectful relations" when he shook hands with U.S. Vice President Joe Biden on the sidelines of Brazilian President Dilma Rousseff's swearing in, he said Friday.

The encounter marked the first top-level meeting between the countries since U.S. President Barack Obama signed a law allowing sanctions against Venezuelan officials suspected of violating the rights of protesters who held anti-government demonstrations last year.

Venezuela confirmed Tuesday that it has entered recession, while annual inflation topped 63 percent, exacerbating the outlook for an economy already hit by crippling shortages and crashing oil prices.

The South American oil giant's economy shrank 2.3 percent in the third quarter, after contracting 4.8 percent in the first quarter and 4.9 percent in the second, the central bank said, the first time it has released the country's growth figures this year.

Venezuelan President Nicolas Maduro, a frequent critic of the United States, congratulated the Castro brothers Friday on Cuba's rapprochement with Washington, but warned that the embargo on the island would remain for a long time.

This month's historic announcement that the United States and Cuba were restoring diplomatic relations after half a century of hostility undercuts the stridently anti-American stance Maduro has adopted as his country slides into a deepening economic crisis.

Venezuela has reacted angrily to a European Parliament resolution accusing the Latin American nation of persecuting the opposition, saying Europe is trying to divert attention from its own financial woes.

Lawmakers at the European Parliament in Strasbourg passed a motion last week urging Caracas to withdraw arrest warrants against opposition politicians, and to disarm and dissolve pro-government associations.

Tighter new U.S. sanctions against Venezuela are aimed to foment violent unrest to try to overthrow President Nicolas Maduro, his defense minister said Saturday.

"This U.S. interference is aimed at promoting violence... against our institutions" to oust staunch U.S. critic Maduro, Defense Minister Vladimir Padrino told Telesur television.

China on Friday criticized a call by the United Nations for North Korea to be referred to the International Criminal Court (ICC) in The Hague over its human rights record.

"It is our long-standing position that countries should engage in constructive dialogue and negotiations to deal with differences on human rights, and we oppose politicizing or using the issue of human rights to put pressure on other countries," foreign ministry spokesman Qin Gang said at a regular briefing.

President Nicolas Maduro charged Saturday that tighter, "stupid" new U.S. sanctions are just further straining to undermine military staff loyalty after Venezuela derailed a bid to oust him.

"These sanctions are a threat -- to see if they can break the morale of leaders of our armed forces... In March, I announced that we put down an attempted coup, thanks to our brass's loyalty," Maduro said at a speech in Caracas.