Updated

More than 30 countries that support a set of principles calling for U.N. peacekeepers to protect civilians in armed conflict are asking the United Nations to go a step further and hold peacekeepers accountable if they fail to do so.

A letter sent to Secretary-General Antonio Guterres Tuesday and obtained by The Associated Press encourages the U.N. chief to consider repatriation and possible financial penalties "when there are substantial groups to believe that troops have failed to uphold protection of civilian mandates."

It also encourages Guterres to take administrative and other measures when peacekeepers fail to implement mandates including "holding accountable and, where appropriate, sanctioning senior mission leadership."

Rwanda, the Netherlands and the United States initiated the principles which were adopted at a high-level meeting in May 2015 in Kigali by the top 30 troop and police contributors to U.N. peacekeeping operations, the top 10 financial contributors, and other nations.

The three countries also initiated Tuesday's letter, which was signed by 32 countries.

When the Kigali Principles were adopted, then U.S. ambassador Samantha Power said they were designed to make sure that civilians aren't abandoned again by peacekeepers when conflicts escalate. She pointed to the U.N. peacekeepers that left Rwanda before the 1994 genocide and Srebrenica before the 1995 massacre.

The principles authorize peacekeepers in missions that have a U.N. Security Council mandate to protect civilians to take "direct military action against armed actors with clear hostile intent to harm civilians." The principles also state that their commanders can authorize force "in urgent situations" without consulting their country's capital.

The letter sent Tuesday said the 32 countries "have pledged to take proactive steps to mitigate potential threats to civilians and to be prepared to use force to protect civilians, as necessary and consistent with the authority granted in the mandate."

"We will take disciplinary action as appropriate, if our personnel fail to act to protect civilians when circumstances warrant," the countries said.

They stressed that the responsibility for accountability and performance of peacekeepers is shared by the countries that provide troops and the United Nations.

"We strongly support your ongoing efforts to uphold this responsibility," the countries said.

The 32 countries then asked Guterres to take action, including repatriation and possible financial penalties, when mandates to protect civilians aren't implemented.

They stressed that these decisions will be difficult.

"However, such decisions are necessary when civilian lives are at stake; and we, as supporters of the Kigali Principles, stand behind you in making them," the letter said.

Guterres has embarked on major U.N. reforms, including in its 14 far-flung peacekeeping missions, focusing on areas such as training, equipment, better communications and accountability.