US President Donald Trump confirmed on Monday that the US had struck a port facility in Venezuela several days ago.

"There was a major explosion in the dock area where they load the boats up with drugs," Trump said.

"Two nights ago, we knocked that out. So we hit them very hard," Trump said.

No details were available regarding damage to the facility, if there were casualties or how it was attacked.

"We hit all the boats and now we hit the area, it's the implementation area. That's where they implement. And that is no longer around," Trump said.

It would be the first known land attack by US forces on Venezuela.

Asked about any CIA involvement, which the president said he had authorized last week, Trump said: "I don't want to say that. I know exactly who it was but I don't want to say who it was. But you know, it was along the shore."

The New York Times alleged the attack was carried out by a CIA drone and didn't cause any casualties. It claimed the attack was on a dock facility run by Venezuelan gang Tren de Aragua, which the Trump administration has designated a foreign terrorist organization.

Venezuela has not commented on the attack, and President Nicolas Maduro has previously denied ties to the drug trade.

"We still have more questions than answers about this operation," Geoff Ramsey, a Venezuela researcher and senior fellow at the Atlantic Council, was quoted as saying by Bloomberg.

"Maduro is unlikely to be intimidated by US covert action in Venezuela if it continues to be used to go after relatively low-level drug-trafficking schemes," Ramsey said.

The attack was seen as the latest increase in US pressure on the government of Maduro, which has included the sinking of more than two dozen boats in the Caribbean that it said were carrying drugs — killing over 100 people in the process — and the seizure of two oil tankers in December, which it claimed were transporting sanctioned oil.

"The United States will continue to pursue the illicit movement of sanctioned oil that is used to fund narco-terrorism in the region," US Homeland Security Secretary Kristi Noem posted at the time.

Critics say Trump is trying to force a change of government in Venezuela, or use the blockade and seizures as a step toward war with the Latin American country. "I don't rule it out, no," Trump said.

The US military has been building up forces in the Caribbean, including the USS Gerald Ford carrier strike group.

Yvan Gil, Venezuela's foreign minister, claimed earlier that Trump wants the country's energy resources.

Venezuela has the largest proven oil reserves in the world, and exported an average of more than 770,000 barrels per day last year.

Numerous ships loaded with millions of barrels of oil are now parked off the coast of Venezuela, unsure whether they should set sail and risk being seized.

shiguang@chinadailyusa.com