The United States consulate, closed since 2017, will resume limited issuing of visas, its embassy in Havana said on Thursday.

The consulate "will begin the limited resumption of some immigrant visa services, as part of a gradual expansion of the embassy's functions," said Timothy Zuniga-Brown, the charge d'affaires at the US diplomatic mission in Havana.

The US reduced its mission to the bare minimum in September 2017, when then-US president Donald Trump accused Havana of carrying out "sonic attacks" against embassy staff in 2016 and 2017.

Staff there and their families had suffered from mystery illnesses.

Similar incidences later occurred at other embassies around the world.

The consulate closure was a major blow for Cubans wishing to emigrate to the US as it obliged them to tackle numerous obstacles, among them being forced to travel to Colombia or Guyana to submit a request.

Zuniga-Brown said the consulate will only schedule appointments with people that have already presented complete document files but that during the transition period most requests will still have to be made in Guyana's capital Georgetown.

The consular service will also provide essential services to US citizens and emergency non-immigrant visas, he added.

According to existing immigration agreements, the US must authorize 20,000 immigrant visas a year to Cubans.

With Cuba suffering its worst economic crisis in 30 years due to the coronavirus pandemic, most Cubans hoping to emigrate to the US have chosen to do so through the dangerous Central American route where migrants face numerous dangers including exploitation by people smugglers.