A hospital official told the German news agency DPA that at least 70 people were killed in the explosion. However, hospital officials have said the number of deaths could be higher.

No group has claimed responsibility for the attack on a police station in Libya, but local authorities have said that groups claiming allegiance to "Islamic State" (IS) have been trying to gain a foothold along Libya's coast.

In the coastal town of Zliten, where the blast occurred, Mayor Miftah Hamadi told the news agency Reuters that the bombing happened in the early morning as 400 or so recruits were gathering for police training.

"It was horrific; the explosion was so loud it was heard from miles away. All the victims were young, and all about to start their lives."

The police station was being used to train Libyan border police, a Zliten security official said.

United Nations envoy to Libya, Martin Kobler, took to Twitter to condemn the attack.

UN Secretary-General Ban Ki-moon condemned the bombing as well and called for a national unity government as "the best way for Libyans to confront terrorism in all its forms."

Power struggle in Libya

IS has been growing in power in Libya, and has recently claimed an attack earlier this week on the oil port town al-Sidra and Ras Lanouf. The militant group has been trying to push east from its coastal stronghold of Sirte in an attempt to seize control of Libya's oil resources.

Libya has been the scene of chaos as armed factions have tried to gain a stronghold since the fall of Moammar Gadhafi in 2011.

The oil-rich country has been deeply divided between the Islamist government based in the capital Tripoli, and the internationally-recognized administration in the east of the country.

smm/rc (AP, dpa, Reuters)