VATICAN CITY — Pope Francis says he is “deeply grieved by the news of the loss of life and grave injuries” caused by two bomb blasts at the Boston Marathon.

Francis expressed his condolences in a message Tuesday addressed to Boston Cardinal Sean O’Malley, a good friend of Francis’ from the pope’s time as archbishop of Buenos Aires, Argentina.

The explosions Monday killed three people, including an 8-year-old boy, and injured more than 140. No one has claimed responsibility.

Francis called on Bostonians to “be united in a resolve not to be overcome by evil but to combat evil with good” and to work together “to build an ever more just, free and secure society for generations yet to come.”