An alliance of Myanmar ethnic minority armed groups said Sunday it had agreed a four-day ceasefire with the junta in northern Shan state following weeks of clashes in which it seized territory from the military along a key highway to China.

"We... showed cooperation with China by agreeing a four-day ceasefire in Northern Shan" from 14-18 July, Major-General Tar Bhone Kyaw of the Ta'ang National Liberation Army (TNLA), one of the members of the alliance, told AFP.

Northern Shan state has been rocked by fighting since late last month, when the so-called Three Brotherhood Alliance renewed an offensive against the military along the road to China's Yunnan province.

The clashes shredded a previous Beijing-brokered truce that in January halted an offensive by the alliance, made up of the Arakan Army (AA), the Myanmar National Democratic Alliance Army (MNDAA) and the TNLA.

The new four-day agreement did not cover the neighbouring Mandalay region, where members of the alliance and other opponents of the military have been battling junta troops in recent weeks, Tar Bhone Kyaw said.

AFP was unable to reach a junta spokesman for comment.