The simultaneous attacks on three churches across Surabaya on Sunday morning killed 14 people, as well as the six suicide bombers, and injured dozens.

In a press statement published on the United Nation’s official website, UN Secretary General António Guterres said he was “appalled at reports saying that children were used to participate in the attacks”.

He added that the UN supported the Indonesian government and its people in their efforts to fight and prevent terrorism and violent extremism.

Separately, Pope Francis addressed the Indonesia people, especially Christians in Surabaya, to say he was praying for the victims and their loved ones. 

(Read also: [UPDATED] Surabaya church bombings: What we know so far)

Leaders of several neighboring countries have also offered their sympathies. 

Singapore’s President Halimah Yacob and Prime Minister Lee Hsien Loong wrote on Monday a condolence letter to President Joko “Jokowi” Widodo, expressing their shock and sadness over the news of the attacks.

Meanwhile, Australian Prime Minister Malcolm Turnbull and Foreign Affairs Minister Julie Bishop said Australia stood in solidarity with Indonesia.

“We offer our sincere condolences to the family and friends of those killed and injured,” they said in a joint statement. “Our two nations share a common commitment to mutual respect and diversity and we reject those who seek to spread division and hatred.”

Meanwhile, Organization of Islamic Cooperation (OIC) secretary-general Yousef Al-Othaimeen condemned the terror acts, reaffirming the OIC’s principle position that violence and terrorism should not be associated with any religion, nationality, civilization or ethnic group.

“Violent extremism and terrorism in all its forms and manifestations, including violence against civilians and suicide attacks, are against the holy principles of Islam and [an] affront to the religious diversity of Indonesian society,” he said.

A family of six blew themselves up at three separate churches in Surabaya on Sunday morning. In the evening, a bomb prematurely went off in a low-cost apartment in Sidoarjo, East Java, killing two members of a family and injuring their children. It is believed that the family had been planning a similar terror attack.

On Monday morning, another bomb went off at the Surabaya Police headquarters. (ebf)