Jakarta – Dialogue between the government and separatists in Indonesia's Irian Jaya province is giving way to brutality with moderates on both sides gagged, rights advocates fear.

Since the December 1 anniversary of an unrecognised declaration of independence, the last day the separatist Morning Star flag was allowed to fly in Irian Jaya, 18 people have been killed.

Both security forces and separatist guerillas in the province, on the western half of New Guinea island, have put their troops on full alert. Two of those killed were police officers, and four were non-native settlers, killed with the arrows, axes and crude spears of their native Papuan attackers.

Eleven were students or independence supporters, shot or beaten to death by police. In the capital Jayapura alone, 155 independence supporters and students have been rounded up in the past fortnight, of whom 12 are still being held.

Among those still behind bars, leaders of the predominantly-moderate Papua Presidium, which has been spearheading calls for independence while preaching non-violence and dialogue.

Despite their proposals to make West Papua a zone of non-violence, and their agreement to ban the flag, police jailed and placed subversion charges on them. Those not jailed have fallen silent.

The effective gagging has left a leadership vacuum in the struggle for independence, a sentiment felt deeply and widely across the former Dutch colony which had been promised independence by its colonisers as they departed in the early 1960s.

Indonesia, by gagging the moderate leaders have also gagged the advocates of non-violence and dialogue, the activists say. "The movement is completely rudderless now," Institute for Human Rights and Advocacy chief, John Rumbiak told AFP. "There is no-one to take responsibility."

In Jakarta, President Abdurrahman Wahid's pleas that the moderate leaders be freed so that dialogue can continue have fallen on deaf ears, with the military and parliament calling for tough action instead.

Public opinion polls suggest most of the Jakarta elite – shocked by the loss of East Timor during a vote for independence last year, and fearing another rebellious province, Aceh, breaking away – are behind force in Irian Jaya.

Even before the agreement to ban the flag after December 1 was enforced, Rumbiak called it "deadly," predicting an increase in grassroots frustration.

Guerillas from the Free Papua Movement (OPM) have been waging a rag-tag war with poison arrows and spears from dense jungles and remote mountains for more than 30 years against Indonesia, whose troops entered in 1962-63, and whose sovereignty was formalised in 1969.

Attacks on police and transmigrants in the past five days and comments by the movement's supreme commander indicate a heightened mobilisation by the guerillas.

"People saw the Presidium as the institution which would bring their aspirations to fruition," OPM commander Brigadier General Richard Hans Joweni told AFP over the weekend. "But they have shown themselves to be partners of Indonesia in supporting autonomy [under Indonesia] instead."

The OPM's highest military commanders met in the deep-jungle border region on November 20-26 to draw up a new manifesto. "The OPM fighters are committed to taking over the independence struggle and authority in West Papua before 2001," it states. "Without compromise, we will take tough action against each person or group who betrays or deviates from the struggle."

Yoweni said the draft guerilla strategies included a December 7 attack on police and the massing supporters at the border with Papua New Guinea. "We are preparing our troops to launch a kind of military offensive, so people are being massed there as part of a political strategy."

The December 7 attack, in which two policemen and a security guard were killed, was meant to "alert the public that we are out there, and we are moving," Yoweni said. The strategy, he said, was "hit-and-run" drawing Indonesian troops from their bases.