Botswana’s president, Mokgweetsi Masisi, has conceded defeat after preliminary results showed his party had lost its parliamentary majority in this week’s election, ending nearly six decades in power.

The private Mmegi newspaper and state radio reported that the ruling Botswana Democratic party (BDP) had lost by a landslide, citing results from more than half the constituencies.

The opposition coalition, Umbrella for Democratic Change (UDC), was in front, putting its leader, the lawyer Duma Boko, on track to win the presidency. Boko has not yet spoken publicly.

At a press conference, Masisi said: “Although I wanted to stay on as your president, I respect the will of the people and I congratulate the president-elect. I will step aside and I will support the new administration.”

Analysts had said the election would be competitive, although the BDP had still been widely expected to win. The party has ruled the southern African country of 2.3 million people since its independence from Britain in 1966.

Mmegi said that based on the results from 36 of the 61 constituencies, opposition parties had won more than half the seats in parliament, which elects the president.

State radio had the same tally. It said that out of the 36 constituencies so far, the BDP had won only one. The UDC had won 25. A party needs to win 31 constituencies to get a majority in this election.

Botswana has enjoyed stability and relative prosperity thanks to its diamond wealth and small population, which gets free healthcare and education. The country is the world’s top producer by value of the gem.

But a downturn in the diamond market has put a squeeze on revenues in the last few years, and the country has struggled to diversify its economy.