Earlier the government had urged civilians to leave the area, giving them a deadline of 4.15pm (1415 GMT).
Military officials, waging their largest offensive against the guerrillas since late March, accused the rebels of holding 3,500 human shields in the villages of Vakcince and Slupcane.
The rebels have denied holding any villagers.
Earlier the government had urged civilians to leave the area, giving them a deadline of 4.15pm (1415 GMT).
Reporters near Vakcince, about 25km (15 miles) north of the capital Skopje, said the new bombardment started half an hour after the deadline passed. They saw heavy artillery, mortars and heavy machinegun fire hitting the area, which was billowing smoke.
"We'll use all available means to eliminate the terrorists," said Defence ministry spokesman Gjorgji Trendafilov. He said the army had inflicted "serious damage" on the rebels since the offensive began Thursday.
Fighting talk
Commander Sokoli, a leader of the rebel National Liberation Army, denied that villagers were being held as shields, and he accused government forces of "indiscriminate attacks against our civilians".
Speaking from his mountain hideout, he told the Associated Press news agency: "It is a pity what is happening to the civilian population with the blessing of the international community."
He said 2,000 rebels were prepared to fight "until the end" to keep Macedonian troops out of the area.
Colonel Blagoja Markovski, an army spokesman, said there were no civilian casualties. But media in Belgrade and Kosovo reported two civilians killed in the fighting in Vakcince, and the mayor of the town of Lipkovo said at least seven people had been killed.
"It is war," the mayor, Hysamedin Halili, told the Kosovalive news agency. "The people are hiding in the basements. They are in the villages and they do not want to leave their houses."
Commander Sokoli said two rebel soldiers were wounded, one seriously. The Macedonian army did not report any casualties on its side.
The army offensive was launched after guerrillas were reported to have killed two Macedonian soldiers in Vakcince on Thursday. A third was said to have been taken captive.
At the weekend four soldiers and four policemen were killed in another ambush in the north-western town of Tetovo, raising tensions in the Balkan country where minority ethnic Albanians are demanding greater rights and recognition.
Nato and the European Union, fearing fresh bloodshed, prepared to send their top envoys to Macedonia.
The EU's security affairs chief, Javier Solana, planned to arrive Sunday for meetings with Macedonian leaders, and Nato Secretary-General Lord Robertson was to join him on Monday.