Venezuela's military has taken charge of food distribution and key ports to guarantee supplies of basic goods and medicines amid increasing shortages and mounting unrest.

President Nicolas Maduro on Tuesday put his military in charge of five sea ports, giving his country's armed forces a major promotion as Venezuela struggles under a dire economic and political crisis.

"Today, we are taking five fundamental ports of the country: Guanta, La Guaira, Puerto Cabello, Maracaibo and Guamache," Maduro said on state television after meeting Vladimir Padrino Lopez, his defence minister general.

The military will oversee production of food and medicine in "a great operation to fight the economic war", Maduro said.

The initiative to boost production and guarantee the smooth distribution of food supplies in the face of what he called economic sabotage by his opponents. 

READ MORE: Thousands of Venezuelans pour into Colombia to buy food

The announcement came weeks after violent protests began over food shortages across the nation.

A drop in oil prices has left Venezuela's economy in tatters, and the lack of hard currency and inflation have starved the country of food, medicine and consumer goods.

On Sunday, Venezuela opened its closed border to Colombia to allow thousands of people to cross to buy food and other staples there.

Suspended factories

The nation's woes have accumulated with multinational firms shutting up shop and, on Tuesday, the US bank Citibank confirming it had closed the government's overseas payments account.

Maduro likened Citibank's move to a "financial blockade".

His government had used the account to make payments in the US and elsewhere in the world.

Citibank's move was the latest in a string of closures or scaling back of operations of foreign companies operating in Venezuela, such as Coca-Cola, US food giant The Kraft Heinz company, Clorox and airlines Lufthansa, Aeromexico and American Airlines.

READ MORE: Venezuela takes over suspended Kimberly-Clark factory

On Monday, Venezuela's government said it was taking over and reactivating a factory belonging to the US company Kimberly-Clark, after the consumer products giant announced last week that it was suspending operations because of the country's deteriorating economic situation.

In the past month, at least five people have been killed in clashes with security forces sparked by food riots.

Source: Agencies