ROME – Jan. 1 is marked by the Catholic Church as the World Day of Peace, but even on this day, Pope Francis was compelled to acknowledge the realities of an oft-violent world, expressing sorrow over an attack on a Turkish nightclub that reportedly left 39 people dead.

“Unfortunately, violence has struck even on this night of well-wishes and hope, with a grave attack in Istanbul,” Francis said on Sunday during his noontime Angelus address on Sunday, delivered before a crowd in St. Peter’s Square estimated at 50,000.

“Deeply saddened, I express my closeness to the Turkish people,” he said, vowing prayers for the dead and injured “and to the entire nation in mourning.”

The pontiff went on to call for an end to the “scourge of terrorism, that envelops the world with the shadow of fear and bewilderment.”

Pope Francis visited Turkey in November 2014.

According to media reports, a gunman opened fire in the Reina nightclub in Istanbul around 1:30 a.m. as revelers were ringing in the New Year. A total of 39 people are believed to be dead, including 15 foreigners, and at least 70 people were being treated for injuries in local hopsitals.

Turkish President Recep Tayyip Erdogan said the attackers were trying to “create chaos” and pledged to “fight to the end” against terrorism.

The gunman was believed to have acted alone, and Turkish police have said a manhunt is underway.

Although no group has taken responsibility for the attack, many Turkish media outlets have suggested involvement by the Islamic State, as ISIS leaders have called on their followers to carry out attacks inside Turkey.

In his Angelus address, Pope Francis recalled that the World Day of Peace is an observance launched by Pope Paul VI in 1967, making this the 50th time the Church has marked the occasion.

Francis began by wishing the large crowd gathered in St. Peter’s Square, buoyed by members of the Community of Sant’Egidio, a Happy New Year.

“It will be happy,” he said, “according to the measure in which each one of us, with the help of God, seeks to do good day after day. That’s how we build peace, saying ‘no’ – with facts – to hate and violence, and ‘yes’ to fraternity and reconciliation.”

Released on Dec. 8, the title of Pope Francis’s 2500-word message for this year is “Nonviolence: A Style of Politics for Peace.” In it, Francis urges the cultivation of a nonviolent response to situations of conflict.

Jan. 1 is also the solemnity of Mary the Mother of God, and Francis also meditated on the role of Mary during his New Year’s Angelus address.

“God asked Mary not only to be the mother of his only-begotten son, but also to cooperate with his son and through the son in his plan for salvation, so that in her and through her, a humble servant, the great works of divine mercy could be accomplished,” he said.

Next Friday, Pope Francis will lead a Mass to celebrate the feast of the Epiphany, traditionally seen by the Vatican as closing the holiday season. On Sunday he’ll celebrate the feast of the Baptism of the Lord, an occasion when the pontiff typically baptizes newborn children of Vatican employees.