Sherritt International Corporation (TSX: S) suspended its direct participation in joint venture activities in Cuba following an executive order issued by the U.S. administration on May 1 that expanded sanctions against Cuba, the company announced.

Three board members - Brian Imrie, Richard Moat and Brett Richards - resigned from the corporation's board of directors effective immediately. The company stated it has not been formally designated under the executive order but noted such designation could occur at any time.

The Toronto-based mining company is repatriating its expatriate employees from Cuba and has requested that partners repatriate their expatriate personnel in Canada. Sherritt communicated these decisions to its Cuban partners in a letter.

Operations at the company's Fort Saskatchewan, Alberta refinery continue producing finished nickel and cobalt. The refinery's current inventory of feed material is expected to last until approximately mid-June.

The executive order may result in financial or other service providers being unable or unwilling to continue supporting Sherritt's operations or business activities, the company stated.

Sherritt operates a refinery in Alberta that the company describes as the only significant cobalt refinery and one of three nickel refineries in North America. The corporation uses hydrometallurgical processes to mine and refine nickel and cobalt.

The company said it will continue consulting with advisors and stakeholders to assess the implications of the executive order.