Venezuelan President Nicolas Maduro has declared a 60-day state of emergency due to what he called plots from within the oil-producing state and from the US to topple his socialist administration.

A previous state of emergency, implemented in states near the Colombian border last year, suspended some constitutional guarantees in those areas.

On Friday, US intelligence officials said they were increasingly worried about the potential for an economic and political meltdown in Venezuela, and predicted Maduro was not likely to complete his term.

Venezuela's opposition is seeking to recall the unpopular leader, 53, amid a worsening crisis that includes food and medicine shortages, frequent power cuts, sporadic looting and galloping inflation.

But the former union leader and bus driver has vowed to stick out his term, and accuses the US of an undercover coup against him.

He pointed to this week's impeachment of fellow leftist Dilma Rousseff in Brazil as a sign that he is next.

"Washington is activating measures at the request of Venezuela's fascist right, who are emboldened by the coup in Brazil," Maduro said on a broadcast on state television.

Washington has had a rocky relationship with Caracas for years, not least because of support from President George Bush for a short-lived 2002 coup against late leader Hugo Chavez, and anti-US rhetoric from Chavez.

"Today Maduro has again violated the constitution,” said opposition lawmaker Tomas Guanipa. "Why? Because he is scared of being recalled."