Top military leaders met in emergency session and troops moved across the southern region of Silesia on Saturday after workers at four more coal mines joined nationwide strikes to demand legalization of Solidarity.

Poland's leader, Gen. Wojciech Jaruzelski, and the national Defense Committee reached "appropriate decisions," the state-run news agency PAP said.The brief dispatch gave no hint about what the government planned to do about the strongest challenge to communist authorities since Solidarity, the independent union federation, was crushed in 1981.

Opposition activists said police columns and army units were on the move in Silesia, where the 10 coal mine strikes were centered.

Unusual police movements also were reported in Krakow and Nowa Huta, the scene of a cripping steel strike last spring.

"There are helicopters flying over Jastrzebie (in Silesia) and many army units near. Police are also erecting roadblocks at the towns' outskirts, just like during martial law," said Adam Slomka, a leader of the rightist opposition group Confederation for Independent Poland, in Katowice.

"We want to appeal to miners to be on the alert, put on all possible lights and make sure they will not take them by surprise."

Solidarity, meanwhile, observed its eighth anniversary. The movement was suppressed with the imposition of martial law in 1981 and outlawed in 1982.

The government rejected the demand to legalize it and said the strikes harmed every Pole.

About 40,000 workers were participating in the coal strikes, which were costing an estimated $1.3 million in lost coal production a day. Production was stopped, but it was impossible to determine what percentage of mine employees actively supported the strikes.

Spirits were high among 2,000 cargo workers occupying the docks of Poland's second-busiest port in Szczecin since Wednesday. Bus and most tram drivers there went on strike Thursday and Friday, crippling public transport.

The four mines that joined the walkouts Saturday were the 3,000-worker Krupinski mine in Suszec, the 3,500-worker ZMP mine in Zory, and the First of May and Borynia mines in Jastrzebie.