STOCKHOLM — Sweden’s general election was headed for a cliffhanger Sunday night, with the opposition bloc led by Social Democrat Magdalena Andersson holding a projected 175 seats in the 349-member parliament, just one more than Prime Minister Ulf Kristersson’s right-wing alliance. The projections were based on results from more than 5,800 of the country’s 6,600 voting districts. The Swedish Election Authority’s count showed Kristersson’s four-party alliance, which includes the nationalist Sweden Democrats, with 174 seats. The final result may not be clear until Wednesday. The narrow margin leaves open the possibility that the Sweden Democrats could enter a Swedish government for the first time. Kristersson has governed since 2022 with the party’s support in parliament but has kept its lawmakers outside the cabinet. He has said that, if his side remains in power, he would appoint Sweden Democrat ministers. Speaking to supporters after midnight Monday, Andersson described the contest as even but said her bloc was currently ahead. “If this holds up, Sweden will get a new government,” she said. Kristersson said the result would make coalition negotiations difficult, while arguing that voters had not given the left a mandate for what he called its “socialist” economic program. “Where it ends remains to be seen,” he told supporters at the Moderates’ election-night gathering. “But we are not in a hurry.” The result marked a dramatic reversal from the campaign’s earlier trajectory. Andersson’s bloc had led by double digits in some polling before its advantage narrowed sharply during the final two weeks. Two exit polls released when voting ended initially suggested a clearer opposition victory, but the gap tightened as more districts reported. The election is being watched across Europe as nationalist parties gain influence in legislatures and governments. The Sweden Democrats, founded in the 1980s by people with neo-Nazi connections, have pushed hardline positions on immigration and crime and are now positioned to gain formal power after years of supporting Kristersson’s government from outside. Andersson, who served as prime minister until 2022, acknowledged that even a left-bloc victory would not remove the Sweden Democrats from Swedish politics. She warned that giving the party ministerial platforms could amplify what she called the “hate” it had spread during the campaign. Kristersson has defended cooperation with Sweden Democrat leader Jimmie Åkesson, saying he can control the party’s role in a future cabinet. He said he would personally appoint ministers and could ensure that only people with experience and sound judgment joined the government. The smaller parties in both blocs are likely to determine who can assemble a governing majority. Kristersson’s alliance is already structured around four parties, while Andersson may face more difficult negotiations among parties that differ on economic and policy questions. The next government will depend not only on the final seat count but also on whether the bloc leaders can reach a power-sharing agreement.