http://www.bbc.co.uk/news/world-africa-13196875The UK "must prepare for the long haul" in Libya, Downing Street has said.
Earlier Foreign Secretary William Hague briefed the cabinet about the situation in Libya.
Number 10 said progress was being made in putting greater pressure on Libyan leader Colonel Muammar Gaddafi and there were "grounds for optimism".
RAF fighter aircraft "successfully attacked" three armoured personnel carriers near the besieged city of Misrata over the weekend.
But a spokeswoman for the prime minister said: "We must prepare for the long haul."
She said this was not a new policy, simply a broad statement of fact, adding: "It is just sensible planning to enforce United Nations Resolution 1973."
The briefing took place as Defence Secretary Liam Fox flew to the US for talks on the best way of increasing pressure on Col Gaddafi's forces.
He will speak to US counterpart Robert Gates while Chief of the Defence Staff General Sir David Richards will also speak to his counterpart.
Before flying to Washington, Dr Fox told the Daily Mail: "If the regime continues to wage war on its people, those who are involved in those command-and-control assets need to recognise that we regard them as legitimate targets.
"Those who are in command-and-control assets, controlling the regime's activities against its own people, would have to recognise the risks they would have if they were there during Nato strikes."
Vehicles destroyed
Earlier, a Nato air strike badly damaged buildings in Col Gaddafi's compound in Tripoli.
Major General John Lorimer has given an update on the military situation.
He said: "Coalition air patrols have continued to focus on the areas around Misrata, Brega and Ajdabiya, and Yafran.
"On Saturday RAF Tornado and Typhoon aircraft successfully attacked three armoured personnel carriers near Misrata, as well as a surface-to-surface missile facility near the city.
"Eight rocket launcher vehicles were seriously damaged and eight support vehicles are assessed to have been destroyed."
"RAF aircraft returned to the same missile facility on Sunday and destroyed rocket storage facilities, as well as a main battle tank nearby," Maj Gen Lorimer added.
"On Monday, UK aircraft engaged a tank near Mizda and a self-propelled gun near Yafran, as well as a number of missile launchers south-west of Misrata."
Topic: Libya: UK should prepare for the long haul - Number 10 (Read 2087 times)