Bells tolled and thousands bowed their heads in prayer in Hiroshima on Thursday at ceremonies marking the 70th anniversary of the world's first atomic bombing.

At 8:15 am, the exact time the bomb exploded on Aug 6, 1945, the crowd stood for a moment of silence in the heavy summer heat while cicadas shrilled, the Peace Bell rang and hundreds of doves were released into the sky.

Prime Minister Shinzo Abe, who in a speech at the ceremony called for abolishing nuclear weapons, repeated his view that legislation moving Japan away from its pacifist Constitution was essential to ensure the nation's safety.

However, Abe also said on Thursday that he would express "remorse" over World War II, as a government panel condemned the country's past aggression against its Asian neighbors.

Abe is preparing remarks for the 70th anniversary of the end of the war. His statement is expected to be released ahead of Aug15, the date Japan surrendered to the Allies.

"I will express remorse over the past war," Abe told reporters.

Hiroshima Mayor Kazumi Matsui urged that nuclear weapons be abolished and demanded the creation of security systems that do not rely on military might.

"Working with patience and perseverance to achieve these systems will be vital, and will require that we promote throughout the world the path to true peace revealed by the pacifism of the Japanese Constitution," he said in a speech.

Abe and his government are pushing security bills through parliament that could send Japanese troops into conflict for the first time since World War II, sparking protests around the country.

Many with memories of the war and its aftermath are scathing about Abe's steps away from Japan's pacifist Constitution, and survivors of the bombing lambasted Abe at a meeting after the commemoration ceremony.

"These bills will bring the tragedy of war to our nation once again," said Yukio Yoshioka, 86. "They must be withdrawn."

Many of those who gathered for the ceremony renewed their calls for peace.

"My grandfather died here at that time, and I keep wondering what he felt then," said Tomiyo Sota. "He was still 21 years old and it pains me to think he died so young."

(China Daily 08/07/2015 page1)