(SOURCE: AL JAZEERA AND NEWS AGEN­CIES)

The first of five Iran­ian oil tankers head­ing to Venezuela to help ease fu­el short­ages has en­tered the coun­try's wa­ters, en­coun­ter­ing no im­me­di­ate signs of US in­ter­fer­ence amid a diplo­mat­ic stand­off.

Amid height­ened ten­sions due to what Venezue­lan au­thor­i­ties de­scribed as threats from the Unit­ed States, the oil ves­sel For­tune of­fi­cial­ly en­tered Venezuela's Ex­clu­sive Eco­nom­ic Zone (EEZ) at about 7:30pm lo­cal time (11.30 GMT) on Sat­ur­day, ac­cord­ing to the ship­ping track­er Tanker­Track­er.

"The first Iran­ian tanker reached the Venezue­lan coasts," the Iran­ian em­bassy in Venezuela said in a Twit­ter post.

"Grate­ful to the Bo­li­var­i­an Armed Forces for es­cort­ing them," it added.

Venezue­lan state tele­vi­sion showed im­ages of a navy ship and air­craft prepar­ing to meet it. The gov­ern­ment of Pres­i­dent Nico­las Maduro had pledged that the mil­i­tary would es­cort the tankers once they reached the EEZ.

For­tune was head­ing to the El Pal­i­to re­fin­ery in Puer­to Ca­bel­lo in north­ern Carabobo state, ac­cord­ing to state tele­vi­sion.

The rest of the Iran­ian ships - the For­est, Petu­nia, Fax­on and Clav­el - are ex­pect­ed to ar­rive in the com­ing days.

The ship­ments have caused a diplo­mat­ic stand­off be­tween the US, Iran and Venezuela, which are both un­der harsh US eco­nom­ic sanc­tions. Wash­ing­ton was con­sid­er­ing mea­sures in re­sponse, a se­nior US of­fi­cial was quot­ed as say­ing by Reuters News Agency, with­out elab­o­rat­ing.

"This [the ship­ment] would be an ex­am­ple of how the Iran­ian regime tak­ing the wealth of the Iran­ian peo­ple and wast­ing in Venezuela on Maduro," Bri­an Hook, the US spe­cial rep­re­sen­ta­tive for Iran, said ear­li­er.

The US re­cent­ly beefed up its naval pres­ence in the Caribbean for what it said was an ex­pand­ed an­ti-drug op­er­a­tion. Pen­ta­gon spokesman Jonathan Hoff­man said on Thurs­day he was not aware of any op­er­a­tions re­lat­ed to the Iran­ian ves­sels.

Venezuela has been locked in a po­lit­i­cal cri­sis for more than a year, with the US and more than 50 oth­er coun­tries recog­nis­ing op­po­si­tion leader Juan Guai­do as the coun­try's right­ful leader and ac­cus­ing Maduro of rig­ging elec­tions in 2018. Maduro has ac­cused the op­po­si­tion of stir­ring up vi­o­lence and of at­tempt­ing a coup with the help of the US.

Iran­ian Pres­i­dent Has­san Rouhani had on Sat­ur­day warned the US against dis­rupt­ing the ship­ments as the oil tankers passed through the Caribbean Sea on their way to Venezuela.

"If the Amer­i­cans cause prob­lems for our oil tankers in the Caribbean Sea, we will al­so cause prob­lems for them," Rouhani said in a tele­phone call with Qatar's Emir Sheikh Tamim bin Hamad Al Thani.

Rouhani stressed that Iran did not want a new con­flict with the US, but his coun­try would re­serve the right to de­fend its in­ter­ests.

"We there­fore hope that the Amer­i­cans will not make a mis­take in this re­gard," said the pres­i­dent, ac­cord­ing to com­ments pub­lished on his of­fice's web por­tal.

The tanker flotil­la is re­port­ed­ly car­ry­ing about 1.53 mil­lion bar­rels of gaso­line and alky­late to Venezuela.

The fu­el from Iran comes at a time when the short­age of gaso­line in Venezuela, chron­ic for years in some parts of the coun­try, has wors­ened dur­ing the coro­n­avirus pan­dem­ic.

Venezuela has the largest oil re­serves in the world, but its pro­duc­tion is in freefall, a col­lapse that ex­perts at­tribute to failed poli­cies, lack of in­vest­ment and cor­rup­tion.

The two na­tions held a close re­la­tion­ship since late Venezue­lan Pres­i­dent Hugo Chavez took pow­er in 1999.