A deadly explosion has struck a huge rally for Ethiopia’s new prime minister shortly after he spoke and was waving to the crowd.

Addressing the country minutes after he was hurried to safety, Prime Minister Abiy Ahmed said “a few people” had been killed and others injured.

He called the blast a “well-orchestrated attack”, but one that failed. He did not lay blame but said police were investigating.

The attack was “cheap and unacceptable,” the prime minister said, and added: “Love always wins. Killing others is a defeat. To those who tried to divide us, I want to tell you that you have not succeeded.”

The explosion in packed Meskel Square in the capital, Addis Ababa, came after weeks of sweeping reforms that had shocked many in Africa’s second most populous nation after years of anti-government tensions, states of emergency, thousands of arrests and long internet shutdowns.

The 42-year-old took office in April and quickly announced the release of tens of thousands of prisoners, the opening of state-owned companies to private investment and the unconditional embrace of a peace deal with rival Eritrea.

Websites were unblocked and opposition figures were invited to dinner. Ethiopians said they could hardly keep up with the pace of change.

Saturday’s rally began as a show of exuberance, with supporters wearing clothes displaying Mr Abiy’s image and carrying signs saying “One Love, One Ethiopia”.

In a cowboy hat and T-shirt, Mr Abiy told the tens of thousands of supporters that change was coming and there was no turning back.

“For the past 100 years hate has done a great deal of damage to us,” he said, stressing the need for even more reforms.

After the explosion the state broadcaster quickly cut away from coverage of the rally, which broke up with people singing, chanting and going back to their homes.