At least one person was killed and dozens were injured after an explosion rocked the capital of Ethiopia in a "well-orchestrated attack" apparently targeting the country's new prime minister.

It occurred just as Prime Minister Abiy Ahmed had just finished speaking to tens of thousands of supporters in Meskel Square in Addis Ababa, the Associated Press reported.

Abiy had earlier said in a televised address shortly after the explosion that "a few people... lost their lives."

But Amir Aman, the health minister, later clarified that one person had died in a hospital after the attack..

"The prime minster was the target. An individual tried to hurl the grenade toward a stage where the prime minister was sitting, but was held back by the crowd." — Seyoum Teshome, a rally organizer

"The prime minster was the target," Seyoum Teshome, a rally organizer, told the AP. "An individual tried to hurl the grenade toward a stage where the prime minister was sitting, but was held back by the crowd."

Three suspects, two men and a woman, were immediately arrested, Seyoum said. The man with the grenade was wearing a police uniform, witness Abraham Tilahun told the AP.

Abiy did not lay blame, but said police were investigating.

“Love always wins. Killing others is a defeat,” he said. “To those who tried to divide us, I want to tell you that you have not succeeded.”

An AP reporter saw more than a dozen injured people, the report said.

Video footage later showed Abiy being rushed from the scene by security guards.

“Prime Minister Abiy and other guests who came in attendance are all fine,” Teshome wrote on Facebook.

State television quickly cut away from coverage of the rally, which has since broken up.

Abiy, 42, took office in April and quickly surprised Africa's second most populous country by announcing a wave of sweeping political and economic reforms. He quickly released tens of thousands of prisoners, opened state-owned companies to private investment and embraced a peace deal with rival Eritrea. He also unblocked websites and opposition leaders were invited to dinner.

Many Ethiopians said they could hardly keep up with the pace of change.

The United States has been among other nations expressing support for the changes in the country, a key security ally.

But not everyone supports the reforms.

Some Ethiopians near the border with Eritrea have protested the peace deal. The Tigrayan People’s Liberation Front, which has been a dominant force in Ethiopia’s government for 27 years, said the announcement of the peace deal had been made before the ruling coalition’s congress met to discuss.

"We see this as a flaw," the group said.

The Associated Press contributed to this story.