YANGON (Reuters) - A ceasefire deal to end Myanmar's long-running ethnic insurgencies is not possible as long as fighting persists, the leader of the country's largest rebel group said on Friday.

Myanmar's semi-civilian government drew international praise in March after 16 rebel groups signed a draft ceasefire accord aiming to end six decades of armed conflict.

But brutal fighting between government forces and rebels has flared in the remote northeastern Kokang region since February, spilling over the border into neighbouring China, where five people were killed by stray bombs last month.

"Until and unless the fighting stops, the nationwide ceasefire agreement will be merely words written on a piece of paper," said Bao Youxiang, the leader of the 30,000-strong United Wa State Army (UWSA), which did not sign the draft pact.

Bao made the comments at a summit of 12 insurgent groups in the town of Panghsang, the de facto capital of UWSA-controlled territory on the China border, and they were included in a Burmese-language translation of the speech seen by Reuters.

Several local journalists also confirmed that Bao had made the comments.

The UWSA had requested Myanmar's government to allow it to govern a self-administered state, Bao said. But he did not say how the government had reacted to this demand.

Bao's comments would not affect the ceasefire process, said Hla Maung Shwe, a senior adviser of the government-linked Myanmar Peace Centre, which has eased the way for peace talks with ethnic groups.

"I've read his speech," he told Reuters. "I just want to say that we now have signed the draft of the nationwide ceasefire agreement and we intend to sign the NCA as soon as possible and to hold political negotiations before the next elections."

The United States has accused the UWSA of raising funds from the drug trade. The group formerly received arms and support from China, and is said to still maintain close ties.

The UWSA-led summit, which is still in progress, includes representatives from three groups that have recently fought the Myanmar army in Kokang and have been excluded from peace talks: the Myanmar National Democratic Alliance Army, the Arakan Army, and the Ta'ang National Liberation Army.

Tens of thousands of people, many of them ethnic Chinese, have fled to China to escape the fighting in Kokang, which has strained ties between the neighbours.

National elections are scheduled for the end of this year.