May 29 is the International Day of United Nations Peacekeepers. At a ceremony in New York, the UN posthumously recognized the men and women killed in 2016 while serving in some of the most dangerous places in the world.

"Our mission for peace will never succeed without courageous people willing to put their lives on the line and we owe you an enormous debt,” said UN chief Antonio Guterres, kicking off the day-long tribute with a wreath-laying ceremony at the UN headquarters in New York.

UN ceremony for peacekeepers in New York./CGTN Screenshot

More than 3,500 peacekeepers have died in the line of duty since the Blue Helmets began operating in 1948. In 2016 alone, 117 military, police and civilians from 43 different countries were killed, many of whom were from African nations.

"It is the families, the spouses, the children, the parents of our peacekeepers who go through the daily anxieties of having a loved one deployed in a distant place for months. We share their anxiety and we offer them our condolences and thoughts for the sacrifices of those who lost their lives,” said Jean-Pierre Lacroix, deputy head of the UN peacekeeping operations.

UN chief Antonio Guterres delivers a speech at the ceremony./CGTN Screenshot

The deceased were posthumously awarded the Dag Hammarskjold Medal, accepted on their behalf by delegates and officials from their countries.

China lost three peacekeepers last year: Sergeant Shen Liangliang, Sergeant Yang Shupeng and Corporal Li Lei were killed in 2016 during peacekeeping missions in Mali and South Sudan.

Two other UN staff from China were also honored at the ceremony – Yang Shaowen, UN's Deputy Police Adviser, and He Mao, one of the first peacekeepers deployed in South Sudan.

In 2016 Chad suffered the biggest loss of life, losing 13 peacekeepers serving in Mali. Senegal and Togo each lost seven peacekeepers in Mali, Cote d'Ivoire and Sudan.

UN officials said peacekeeping missions have become much more complex in a time of multiple crises. Conflicts are increasingly borderless, peacekeepers are being targeted, and UN's "Blue Helmets" find themselves dealing more with criminal groups than political ones. So far in 2017, 30 peacekeepers have lost their lives.