At least 70 people have been killed after a truck bomb exploded at a police camp in Libya’s north-western coastal city of Zliten.

Dozens were also injured in the suicide bombing on Thursday that occurred when a crowd of policemen were gathering at the camp in the morning, witnesses said.

The truck, packed with explosives, crashed into the gate of the camp, which is used to train coastguards, according to the witnesses.

Most of the casualties are believed to be policemen.

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Hospitals in Zliten, about 160km east of the capital Tripoli, have appealed to local residents to donate blood for the injured victims of the attack, Libya’s official news agency LANA reported.

UN envoy on Libya, Martin Kobler, denounced the attack.

“I condemn in the strongest terms today’s deadly suicide attack in Zliten, call on all Libyans to urgently unite in fight against terrorism,” the German diplomat said in a tweet.

No one has claimed responsibility for the attack, but the bombing is suspected to have been carried out by loyalists of the Islamic State terrorist militia.

“We have information that a boat carrying strangers arrived in the town two days ago,” Siarj al-Rashdi, an official at the Zliten security directorate, told dpa.

“Yesterday we mounted a campaign to collect all strangers staying in the town illegally. But unfortunately, this did not stop the disaster.”

Zliten, a commercial town not known for sheltering militants, is regarded as a centre for illegal migrants seeking to reach Europe.

Libya has been gripped by fighting between rival militias since the 2011 uprising that toppled longtime dictator Muammar Gaddafi.

The oil-rich country is also split between two competing parliaments, each backed by different militias. Islamic State has taken advantage of the anarchy to establish a foothold in Libya.