By Aung Hla Tun and Jared Ferrie
YANGON (Reuters) - The Myanmar army said that a deadly artillery attack on an insurgent military academy had been intended only as a "warning" strike, local media reported, amid mounting tensions ahead of renewed negotiations for a ceasefire.
Twenty-three cadets were killed on Wednesday when a shell hit the training centre on the outskirts of Laisa, the Kachin Independence Army (KIA) capital on the border with China in Kachin State.
Col. Than Aung, minister of border security in Kachin State, said the army was not aware that training was going on in the area and that the site was not the intended target, according to a report on The Irrawaddy web site.
"We feel very sorry for this loss of life and we hope the peace process will not be affected," he told a news conference in the Kachin State capital of Myitkyina on Thursday.
La Nan, a spokesman for the KIA, denied the claim that the artillery attack was an accident. "The school is only about 6 km (4 miles) away from them and they were able to pinpoint the target very easily," he said by telephone. "We're sure they attacked on the school on purpose."
A senior military official told Reuters the attack - the deadliest since a ceasefire agreement broke down in 2011 - came amid rising tensions between the military and the KIA, which he said had shelled government soldiers building a road near Laisa.
The attack comes as representatives from various ethnic armed groups prepare to meet military officials for the next round of negotiations on a nationwide ceasefire, which the government has said it wants before next year's election.
The latest round of peace talks between guerrilla groups and the semi-civilian government that took over in 2011 after nearly 50 years of military rule ended on Sept. 27 without agreement.
Most of the rebel groups have been battling for greater autonomy under a federal system but the military has long stressed the need for strong, centralised government, as set down in a 2008 military-drafted constitution.
Gun Maw, deputy commander of the KIA, said recent attacks were intended to pressure the KIA to sign an agreement with terms favourable to the military and could be a ploy to delay the elections.
(Editing by Jeremy Laurence)