MANILA, Philippines (AP) _ Communist rebels ambushed an army convoy on a mountain road Thursday, killing eight soldiers, a Filipino reporter, and a veteran news photographer.

Defense Ministry spokesman Eddie Pangilinan said it was the first time journalists had been killed covering the 17-year communist insurgency in the Philippines.

Elsewhere, separatists in Cagayan de Oro prepared to declare their southern island of Mindanao an independent nation, and army chief Gen. Fidel Ramos ordered the arrest of anyone violating the country's sedition laws.

Ramos issued the order in Manila as former presidential candidate Reuben Canoy wrapped up plans for a convention of his supporters to approve a 31-page constitution proclaiming the Federal Republic of Mindanao. The separatists were to meet Friday at a college in Cagayan de Oro, about 500 miles south of Manila on Mindanao.

Two soldiers and another Filipino news photographer were wounded in the rebel ambush and 45-minute gun battle on an isolated road about 30 miles north of Taguegarao, Cagayan province.

A defense ministry report said 10 heavily armed men in fatigues attacked two jeeps carrying the soldiers and journalists in the area 210 miles north of Manila.

Those killed included Wilfredo ''Willie'' Vicoy, a photographer for Reuters who had worked for United Press International for 28 years. He died in a Tuguegarao hospital Friday morning, said a colleague at Reuters' Manila bureau who spoke on condition of anonymity.

Ambushes and limited battles in several parts of the islands have continued despite calls by President Corazon Aquino for an end to the fighting.

The journalist who died at the scene was identified by military authorities as Pete Mabaza, a stringer for the Manila newspaper Tempo.

Col. Alberto Sudiacal, deputy commander of a brigade involved in a weeklong battle with insurgents, was among those killed, and brigade commander Col. Selmo Cunanan was among the wounded, the military report said.

Wounded Tempo photographer Albert Garcia said in a telephone interview that he, Vicoy and Mabaza had gone to the battle-torn area with the military unit and were returning in the convoy when they were attacked.

Garcia was confined at a Manila hospital.

Vicoy, who was 45, was one of Manila's most experienced news photographers. He covered the Vietnam War for UPI and had worked on assignment in several Asian countries. His photos have been published in newspapers and magazines around the world.

In Cagayan de Oro, separatists prepared to declare their southern island of Mindanao an independent nation, and army chief Gen. Fidel Ramos ordered the arrest of anyone violating the country's sedition laws.

Canoy, who received only a few thousand votes in the Feb. 7 election and has not previously been identified with the long-simmering separatist movement, promised a peaceful convention.

He did not say how many people supported his movement, but that he expected 500 delegates at the convention, 50 of whom were staying at his house Thursday night.

''I think the people in Manila are overreacting,'' he said.

Ramos said he fears the separatist movement will cause instability.

''The danger here is from other groups, domestic or even foreign, that have evil designs on our government, especially at this time. That threat cannot be minimized,'' he said. ''This is what Mr. Canoy and others may not realize.''

Ramos' arrest order did not specify if participation in the convention would be seditious.

But another army general, Jose Magno, said in Cagayan de Oro that his troops would arrest anyone at the convention who raises the Mindanao flag the separatists have designed or pledges allegiance to the would-be republic.

There have been repeated separatist campaigns on Mindanao in recent decades, the last during the 1970s when more than 60,000 people were killed. Most of the movements were led by Moslems, who say they are mistreated by the Roman Catholic government in Manila. About 2.5 million of Mindanao's roughly 13 million residents are Moslem.