Election Commission officials say that with 97 percent of the vote counted, Gruevski's conservative VMRO-DPMNE party won 48 percent of the vote. The opposition Social Democrats (SDSM) finished a distant second with 23 percent, followed by the ethnic-Albanian Democratic Union for Integration (BDI) with 11 percent, and the Democratic Party of Albanians (PDSh) with 10 percent.
The poll was marred by violence in the country's ethnic-Albanian areas between supporters of the rival BDI and PDSh. Authorities suspended voting in 22 polling stations due to allegations of fraud and intimidation.
Revotes will be held in these precincts, which make up only a small portion of the electorate, but could affect the final balance between the two main Albanian parties.
In claiming victory, Gruevski also acknowledged the vote was far from problem-free.
"Now we can say that Macedonia's rebirth continues," Gruevski said. "I would like to congratulate all citizens for today's elections. In most polling places in Macedonia, we had fair and democratic elections. Unfortunately, in some areas, there were incidents and some irregular voting. VMRO-DPMNE and the Coalition for a Better Macedonia will do everything in our authority to hold revotes in these places so that every member of parliament will be chosen in a fair and democratic way."
Fueled By Anger Over Greece
Elections weren't expected until 2010. But analysts say that with a high approval rating, Gruevski was looking to seal four more years for his ruling coalition. Observers see his victory as fueled by anger over Greece blocking Macedonia's NATO membership invitation at the alliance's April summit in Bucharest.
Hundreds of the prime minister's supporters celebrated in central Skopje, waving flags and chanting Gruevski's name.
The leader of the opposition Social Democrats, Radmila Sekerinska, congratulated Gruevski, but added that due to the violence, "the price Macedonia had to pay was too high."
Macedonia is seeking to join the European Union, in addition to NATO, and the West is alert to any instability in the volatile Balkan country.
Sekerinska added that the SDSM did well, considering what she called its disadvantage in paid advertising.
"Even with a five-to-one disadvantage in paid political advertising on television, it was still possible to get citizens, one by one, to get on the side of [SDSM]," she said. "I would like to show them that this is a team that is moving forward. This is a team that says, 'That which doesn't defeat us will only make us stronger.'"
One man was killed and nine wounded in violence among ethnic Albanians on election day. Gunfire halted voting in one town. Ballot boxes went missing. Two election officials were held briefly by gunmen before being freed unharmed by police.
International observers are expected to present their assessment of the vote on June 2.
Animosity between the two ethnic-Albanian parties has been intensifying since elections in 2006, when the BDI -- which won more ethnic-Albanian votes -- was left out of Gruevski's coalition government in favor of the rival PDSh.
Not Recognize Results
BDI leader Ali Ahmeti said due to the violence, his party would not recognize election results in seven municipalities, including in the main ethnic-Albanian town of Tetovo. He also accused police of colluding with his rivals.
"I would like to underline that those criminal groups have had the support of police and state structures," he said. "So the state cannot avoid responsibility [for the violence]."
PDSh leader Menduh Taci, meanwhile, urged the BDI to recognize the election results. Taci addressed his supporters at a rally in Tetovo as music blared from loudspeakers, with supporters waving flags and shooting into the air.
"I think that BDI should recognize the results. I believe that in some places there should be a revote," he said. "I believe that from tomorrow we will have good relations with the opposition."
Gruevski's next task is to form a ruling coalition in the 120-seat parliament. The prime minister has said he prefers to continue his alliance with the dpa, despite the fact that it again finished behind the BDI -- a move which would further alienate that party's supporters.
RFE/RL's South Slavic and Albanian Languages Service contributed to this report