The Peace Memorial Park in Hiroshima and the Pearl Harbor National Memorial in the US state of Hawaii have established sister ties despite dissent by people including atomic survivors.

A signing ceremony was held at the US Embassy in Tokyo on Thursday.

Hiroshima City Mayor Matsui Kazumi and US Ambassador to Japan Rahm Emanuel signed a sister park agreement.

Based on the agreement, the two parks plan to organize peace events for young people and share ideas and expertise about how to attract more visitors.

A group of organizations whose members include atomic bomb survivors had asked Hiroshima City to suspend the plan to establish sister ties.

The group argued that the meaning and aim of such ties was unclear as the decision was made abruptly without discussions involving citizens and atomic bomb survivors.

Mayor Matsui said at a news conference that he believes the agreement will become a major step toward realizing an international community that can contribute to peace.

He said he was aware of citizens' concerns, but reflected long on the idea before he made the decision as mayor.

Emanuel told NHK that the main purpose of the agreement is reconciliation.

He said he hopes it will inspire citizens in Japan and the United States to learn from what happened in Hiroshima and Pearl Harbor.

The ambassador added that he understands anger and anguish that exist in both countries, but that people have to look to the future and not be held captive by the past.

A civic group co-led by former Hiroshima Mayor Akiba Tadatoshi on Thursday submitted a petition to the city, asking it to scrap the agreement.

It said the park in Pearl Harbor is designed to inspire US forces, and that it is the point of origin for justifying the US atomic bombings of Hiroshima and Nagasaki.

The group said the US side argues that the two parks have common goals, but that the city of Hiroshima should make it clear what common ground they have.

It added that since the agreement was signed so abruptly, the city should scrap it and discuss the matter with the public.