Myanmar military air strikes on a concert held by the Kachin Independence Army (KIA) killed at least 60 people and wounded 70, the KIA said on Monday.

Around 8:40 pm (1440 GMT) Sunday, two Myanmar military jets attacked a ceremony the KIA was holding, its spokesman Colonel Naw Bu told AFP.

"Around 50 people were killed including KIA members and civilians," he said, adding that around 70 were wounded.

The concert, celebrating the 62nd anniversary of the Kachin Independence Organization (KIO) was held at a KIA base also used for military training

Local media reported that up to 60 soldiers and civilians had been killed, including singers who had been performing at the event in Hpakant township in the country's north.

They also reported that the Myanmar military blocked access to medical care for the injured.

Images shared by local media purported to show the aftermath, with debris littering the ground.

The United Nations' office in Myanmar said it was "deeply concerned and saddened by reports of airstrikes that took place in Hpakant, Kachin State".

"Initial reports suggest that over 100 civilians may have been affected by the bombing," it said in a statement.

"Numerous fatalities have also been reported," it added.

A junta spokesman did not respond to a request for comment.

The US Embassy in Yangon said it was "following reports of a military airstrike targeting a Kachin gathering resulting in the deaths of a large number of civilians".

Amnesty International called the strike "part of a pattern of unlawful aerial attacks by the military which have killed and injured civilians in areas controlled by armed groups".

The KIA has clashed regularly with the military for decades, with heavy fighting erupting in the wake of last year's coup.

Last May, it said it downed a military helicopter gunship during fierce clashes near the town of Momauk in the far north.

- Escalating violence -

Myanmar has been in turmoil since a military coup last year, with swathes of the country engulfed by fighting.

Reports of the strikes come days before Southeast Asian foreign ministers will hold emergency talks to discuss Myanmar ahead of November's Association of Southeast Asian Nations (ASEAN) leaders' summit.

The ASEAN has spearheaded so far fruitless efforts to resolve the crisis, and the bloc is frustrated by escalating human rights atrocities.

In September, at least 11 schoolchildren died in a military strike on a Myanmar village in northern Sagaing region.

The junta said it had sent troops in helicopters to Let Yet Kone after receiving a tip-off that fighters from the KIA and a local anti-coup militia were moving weapons.

More than 2,300 people have been killed in the military's crackdown on dissent since the coup and over 15,000 arrested, according to a local monitoring group.

The junta blames anti-coup fighters for the deaths of almost 3,900 civilians