President Jacob Zuma gave a largely upbeat assessment on Tuesday of the health of Nelson Mandela, the nation’s first black president, who has been hospitalized for a lung infection and gallstones.

Gunmen attacked a supply tugboat off the coast of Nigeria’s southern delta, officials said Monday, and Italy’s Foreign Ministry said three of the four kidnapped sailors were Italian.

Recent violence targeting vaccination campaigns threatens the effort to eradicate polio in the three countries where it remains endemic.