Washington and the UK have joined the UN Support Mission In Libya in its call on the Libyan authorities to investigate the killing of 15 migrants in Sabratha.

Last Friday, rescue workers in Sabratha recovered around 15 bodies belonging to illegal migrants and asylum seekers. Some bodies were found burned inside a docked boat, and others were lying on the shore.

"We strongly condemn the reported killing of at least 15 migrants and asylum seekers in Sabratha. We call on Libyan authorities to swiftly investigate this horrific attack, prosecute the criminals involved, and intensify efforts to combat human trafficking to the fullest extent, the US embassy stated on Twitter on Sunday.

For her part, the British Ambassador to Libya, Caroline Hurndall, shared on her Twitter account the UN's statement on the incident and reiterated her country's support for the mission's demands.

"This abhorrent event must be investigated, and the perpetrators brought to justice, and the criminal networks that exploit migrants and asylum-seekers must be tackled and dismantled," Ambassador Hurndall tweeted.

Earlier on Sunday, the UNSMIL called on the Libyan authorities to ensure a prompt, independent, and transparent investigation and bring all the perpetrators involved in the incident to justice.