British oil company BP said it is withdrawing some non-essential staff from Libya after Britain's government warned about deteriorating security in the capital Tripoli.

"We are taking some non-Libyan staff out of the office in Tripoli following advice by the foreign office," the spokesman said. The foreign office advises against all travel to parts of Libya.

The British embassy said on Friday it was cutting staff due to growing unrest in the capital, where armed groups seized two government ministries in late April to press demands on parliament, heightening fears clashes could break out in Tripoli.

A deal to hand over the Foreign Ministry to a committee was reached late on Saturday ending the sieges, but it was not clear whether the armed groups, who call themselves "revolutionaries", would leave the capital for good.

Almost 2 years after the ouster of Muammar Gaddafi in the 2011 war, Libya's new rulers have struggled to impose their authority on a country awash with weapons, and swathes of the oil producing desert country remain out of government control.

Despite concerns raised by international oil firms operating in the OPEC producer, Libya has said foreign security will not be allowed at its oil fields.

In January, BP said it was reconsidering plans to drill for oil in Libya due to increased worries about safety.