The developments come after Venezuelan President Nicolas Maduro claimed in an interview with ABC News on Monday that the United States is trying to "fabricate a crisis" to start a war in South America.

In the past few days, US reconnaissance aircraft have made an increased number of flights in international airspace off the coast of Venezuela in a bid to obtain classified information, the unnamed defence sources told CNN on Tuesday.

The sources did not detail which US spy planes were being used for the mission, but unconfirmed social media reports identified one of the aircraft as a USAF Boeing RC-135V.

READ MORE: 'People Worldwide Will Rise' to Defend Venezuela if US 'Empire' Invades — Maduro

The aircraft reportedly flew off Venezuelan cost for six hours to gather information on the country's missile defence systems, including the sophisticated Russian-made air defences S-300.

USAF RC-135V Rivet joint 63-9792 tracking off the coast of #Venezuela pic.twitter.com/ze2fqVAIac — Manu Gómez (@GDarkconrad) 25 февраля 2019 г.

The alleged flyovers came after Venezuelan President Nicolas Maduro blamed the United States for trying “to fabricate a crisis to justify political escalation and military intervention in Venezuela to bring a war to South America”.

#BREAKING: After a 6 hours flight from Offutt AFB, Omaha, a #USAF RC-135V collected radio & electronic signals to detect latest positions of various units of #Venezuela Army & Air Force tonight that includes SAM systems. This helps #USAF to carry-out precise air strikes.#25feb pic.twitter.com/Nrr0sW9V21 — Babak Taghvaee (@BabakTaghvaee) 25 февраля 2019 г.

Speaking to ABC News on Monday, Maduro also said that US President Donald Trump needs to fix his policy over Venezuela, adding that he is ready for a direct dialogue with Washington and that “the Cold War should stay behind”.

READ MORE: Maduro Accuses US of Using Humanitarian Crisis as Cover for Military Plans

Last week, Trump stressed that “all options are on the table” when it comes to resolving the ongoing political standoff in Venezuela which escalated on 23 January, when opposition leader and President of the National Assembly Juan Guaido declared himself the interim president of the Latin American country.

Shortly after the United States and its several allies recognised Guaido, Maduro, for his part, accused Washington of trying to orchestrate a coup in his country. Russia, China, Cuba, Bolivia and a number of other states reaffirmed their support for constitutionally elected Maduro as Venezuela’s only legitimate president.