Libya’s interim government says a day of militia fighting for control of the international airport in the capital Tripoli has killed 22 people.

In a statement early Sunday, it said “heavily armed groups” have shelled “civilian targets” endangering thousands of citizens and leaving hundreds of families displaced.

The 22 people were killed on Saturday alone, the latest casualties in fighting that has claimed more than 200 lives in recent weeks.

The Royal Navy is reported to be preparing to evacuate Britons from Libya amid escalating violence in the north African state.

The survey ship HMS Enterprise is heading for the port of Tripoli and is expected to moor offshore on Sunday, Sky News reported.

A launch protected by armed Royal Marines is expected to be sent into the port to pick up British citizens and carry them to safety on board the Plymouth-based Enterprise, which is thought to have been diverted from duties in the Mediterranean to help the rescue effort.

The Ministry of Defence (MoD) declined to comment on the reports.

An MoD spokesman said: “As the FCO (Foreign and Commonwealth Office) has made clear, the UK Government will provide assisted departure for a number of UK nationals before suspending consular operations on Monday.

“For operational reasons we will not discuss further details including whether, and in what ways, the MoD could support these efforts.”

Between 100 and 300 Britons are believed to be in Libya, where fighting between rival militias has forced the UK to shut down its embassy.

Libya is in the grip of its worst violence since the 2011 uprising that toppled longtime dictator Muammar Gadafy.

Islamist militias from the coastal city of Misrata have led the assault on airport, seeking to seize it from militias from the mountain town of Zintan. The fighters are mainly former rebels who toppled Gadhafi with the aid of NATO airstrikes.