TAUNGGYI, Myanmar (Reuters) - Myanmar's military has killed about 30 members of what it has described as a Rohingya Muslim militant group, state media said on Monday, marking the largest escalation of the conflict since fighting erupted in the northwest a month ago.

The weekend's killings in restive Rakhine state have essentially destroyed any hopes for a swift resolution to the fighting and a gradual restoration of communal ties, observers and diplomats say.

Soldiers have poured into the Maungdaw area along Myanmar's frontier with Bangladesh in the north of Rakhine, responding to coordinated attacks on three border posts on Oct. 9 in which nine police officers were killed.

Security forces have locked down the area, where the vast majority are Rohingya Muslims - shutting out aid workers and independent observers - and conducted sweeps of villages.

Skirmishes took place throughout the weekend with state media reporting casualties sustained both on Saturday and Sunday. The total death toll from the weekend was unclear, but included at least 28 alleged attackers and two soldiers.

This has increased the number of casualties since Oct.9 to more than 60 for the suspected Rohingya Muslim attackers and 17 for the security forces, according to a Reuters estimate based on reports by state-owned media.

The violence is the most serious to hit Rakhine since hundreds were killed in communal clashes in 2012.

Myanmar's 1.1 million Rohingya Muslims are the majority in northern Rakhine but they are denied citizenship, with many Buddhists regarding them as illegal immigrants from neighboring Bangladesh. They face severe travel restrictions.

Residents and human rights advocates have accused security forces of summary executions, rapes and setting fire to homes in the recent violence.

Satellite images showed a widespread destruction of Rohingya villages, including some 430 homes that have been burnt down, Human Rights Watch said on Saturday, adding the destruction was worse than initially feared.

The government and the army reject the accusations, saying they were conducting "clearance operation" in the villages in accordance with the rule of law. They have blamed the "violent attackers" for setting fires to homes.

On Sunday, the military killed at least 19 people after coming under attack from a group wielding machetes and wooden clubs, the state-owned Global New Light of Myanmar said.

On Saturday, the army killed six people and called in helicopters to reinforce, the paper said.

Three more bodies of suspected attackers were found "in the aftermath of the clearance operation", it said.

Rohingya rights advocates have spread online video clips showing what they claimed were civilian casualties of the attacks, calling on the international community to investigate.

Because access for independent journalists to the area has been cut, Reuters could not independently verify either the government accounts or the video clips.

(Reporting by Antoni Slodkowski; Editing by Nick Macfie)