HAVANA— US lawmakers visiting Cuba urged the State Department on Wednesday to restore embassy staff pulled from the country last year in response to mysterious ailments among diplomats and their families.

The visit by six Democratic members of the Senate and House of Representatives came as the State Department decides whether to send its personnel back to the island.

A decision is expected by March 4.

Secretary of State Rex Tillerson said the symptoms, which included nausea, dizziness, and headaches, resulted from ‘‘targeted attacks’’ and cut embassy staff by 60 percent in September.

Vermont Senator Patrick Leahy and other members of the delegation told reporters in Havana that Cuban officials have cooperated with US authorities in an investigation into the cause of symptoms and that the cut to embassy staff only hurts bilateral relations.

Massachusetts Representative Jim McGovern said the cuts are also hurting ordinary Cubans, who can no longer get basic services from the now eerily quiet US Embassy.

‘‘Making it virtually impossible for the average Cuban to go the United States, whether it’s for a funeral, wedding, or to be able to be with their families, betrays our values,’’ McGovern said.

associated press