Jakarta – Rebels in Indonesia's Aceh are still a major security threat despite a 10-month-old military offensive, an army spokesman said on Monday, a day after the president expressed hope martial law could soon be lifted.

Lieutenant-Colonel Ahmad Yani Basuki, a senior spokesman for the military in the province of Aceh, said the armed forces had not given any input to the government about lifting martial law. He declined to say if the military would support lifting the emergency status, which was imposed last May.

"We have been able to suppress GAM's power but they remain a major threat to the Republic of Indonesia," said Basuki, referring to the Free Aceh Movement (GAM).

On her first visit to Aceh since she imposed martial law and ordered the offensive last May, President Megawati Sukarnoputri said on Sunday that the emergency status could be lifted in two months if the situation was peaceful enough.

The military is involved in its biggest operation ever to crush GAM, which has fought for independence in resource-rich Aceh on the northern tip of Sumatra island since 1976.

"As far as I know I see no indication that the military leaders have specifically advised the government to do so," Basuki said, when asked if the military had told the government it could lift martial law by May.

"But certainly the military would study every decision taken by the government." GAM representatives were not available for comment, nor were senior military officials in Jakarta.

Megawati's decision to impose martial law was applauded by the military – which has good relations with the president – and also won support from ordinary Indonesians, who have little sympathy for separatists.

But the financial costs of the offensive are mounting, as are accusations of rights abuses by the military, charges it denies.

The military says it has killed or captured 3,000 GAM members since May, although the figure is hard to verify as Aceh is largely off limits to foreign media.

Martial law paved the way for the military offensive, which followed the collapse of peace talks with GAM. It was initially imposed for six months last May, then extended in November.

Officials say major GAM figures remain at large, while fighters are taking a hit-and-run approach in remote parts of the province, and in urban areas have faded into the general population to wait for the right time to pick up hidden weapons.