North Korea's powerful military has held a mass rally in the capital, Pyongyang, to pledge loyalty to the country's new leader Kim Jong Un.

Armed forces chief Ri Yong-Ho read the pledge of loyalty to Kim Jong Un of the three branches of the military. In typically exaggerated language, the pledge promised to “wipe out the enemies to the last one if they intrude into the inviolable sky, land and seas of the country even 0.001 mm.”

“We will become ten thousand rifles and ten thousand bombs to serve as the supreme commander Kim Jong Un's first line of lifeguards and Kim Jong Un's first line of death-defying corps.”

During the rally, navy officers promised to “become rifles and bombs” to protect their leader.

“If the enemies intrude our sea even by one inch, we, the navy who protects our country's sea, pledge that we will bury them at sea forever by a firm and merciless strike, and we also pledge that we will advance the day when we bring our supreme leader to the naval port on the South Sea of unified land.”

The rally ended with a march.

Pyongyang also announced a rare amnesty for prisoners, starting February 1. The official news media said the amnesty would apply to “convicts,” but it did not give numbers or elaborate on who would benefit.

North Korea proclaimed Kim Jong Un the successor of his father Kim Jong Il, who died last month. Kim Jong Un, who is in his late 20s and does not have active military experience, has been appointed supreme commander of the 1.2 million-member military.

Rights groups say that thousands of people are held in North Korea's prisons and labor camps, mostly for political and not criminal reasons.

This year the country marks the 70th anniversary of the birth of Kim Jong Il and the 100th anniversary of the birth of Mr. Kim's father, North Korea's founding President Kim Il Sung. The amnesty is in commemoration of the two events, but observers say it is part of the effort to get wider support for the new leader.