One person was killed and nine wounded in shootouts between rival ethnic Albanian groups or in standoffs with police, prompting voting to be suspended in 22 polling stations because of intimidation, violence or reports of ballot fraud.
The violence could jeopardise the Balkan country's bid for membership in the European Union and Nato, but Gruevski said Macedonia "has the energy for progress, to join Nato and EU".
The authorities said 21 people had been arrested.
Ivo Kotevski, an interior ministry spokesman, said those arrested included Agim Krasniqi, a former rebel commander.
In 2004 Krasniqi reportedly led a 50-strong armed group into a village north of Skopje claiming the government and ethnic Albanian leaders had broken promises to provide former rebels with amnesty and jobs.
Gruevski's centre-right VMRO-DPMNE party won nearly half the votes in more than 80 per cent of the polling stations, Jovan Josifovski, head of the state election commission, said.
|Preliminary results give the PM's party the |
biggest majority in more than 10 years [AFP]
Preliminary results have put Gruevski's party far ahead of the Social Democrats' 22.19 per cent, giving the conservative VMRO-DPMNE the healthiest majority in Macedonia's parliament in more than 10 years.
The Democratic Party of Albanians (DPA) led by Menduh Thaci had 10.13 per cent while the rival ethnic Albanian Democratic Union for Integration (DUI) had 11.26 per cent.
If Gruevski fails to win a landslide he is likely to need the support of the DPA or the DUI to form a government.
Radmila Sekerinska, head of the Social Democrats, criticised the conduct of the election, saying it was "the worst organised elections".
"The price that we have paid today is too high because there were a loss of human life, violations, shootings," she said.
"I hope the wining coalition will consider that and will understand that this behaviour was unacceptable."
Erwan Fouere, head of the European Union office in Macedonia, said he was "deeply concerned" by the situation.
"We have appealed to the government and the state authorities to do everything possible to prevent further violence," he said.
Ethnic Albanians make up a quarter of Macedonia's 2.1 million people.
Rebels fought a six-month insurgency in 2001 for more rights, but now the minority's two main parties are locked in bitter rivalry.
|Voting was suspended in 22 polling stations |
due to violence or reports of fraud [AFP]