UPDATE 2-Cameron says Britain will train Libyan security forces
(Adds more quotes, decision by EU on training mission to Libya)
TRIPOLI Jan 31 (Reuters) - British Prime Minister David Cameron used a surprise visit to Tripoli on Thursday to pledge Britain's help in training Libya's security forces, part of broader European efforts to counter Islamic militancy in North Africa.
In Brussels, European Union foreign ministers approved the outline of a mission to help Libyan authorities tighten border security to combat arms-smuggling and stop militants crossing the border. The training and advisory mission is expected to involve about 70 civilian experts and to be launched by summer.
Concern over security in the vast tracts of the Sahara has grown after Islamic militants seized hostages earlier this month at Algeria's In Amenas gas plant. Up to 37 foreigners died after troops stormed the complex to end the hostage crisis, which saw the killing of 29 hostage-takers.
Cameron flew into Tripoli from Algiers, where he also pledged to cooperate on security and intelligence. In the Libyan capital he visited a police training academy and Martyrs' Square. He has called North Africa and the Sahel a "magnet for jihadists" and warned of a "generational struggle" against them.
However, he has shied away from a major military response and instead espoused empowering regional governments to take the lead in security and bolstering the rule of law and democratic institutions.
"There is no true freedom and no true democracy, without security and stability as well. We are committed to helping with that both here and also in your neighbourhood," Cameron said at a news conference with Libyan Prime Minister Ali Zeidan.
"We've agreed a package of additional help from Britain to Libya - increasing the military training we are providing, increasing the police advisers ... We've also discussed how we can help build the institutional capacity of the new Libyan government," he added.
Cameron last visited Libya in 2011 along with then French President Nicolas Sarkozy after rebels ousted former Libyan leader Muammar Gaddafi with French, British and U.S. backing.
At the time he called Benghazi, the cradle of the uprising against Gaddafi, an "inspiration to the world".
Since then, Libya's second city has been disrupted by violence and become a base for Islamist militant groups. Last September an attack on the U.S. diplomatic mission killed the U.S. ambassador to Libya and three other Americans.
Last week Britain urged its citizens to evacuate the city, citing a "specific, imminent" threat, irking Libyan officials keen to attract foreign money and expertise after decades of under-investment during Gaddafi's rule.
"Our security situation is good, we are recovering, things are getting better ... I would like to highlight that what was raised about Benghazi is just some propaganda, made by opponents to the Feb 17th revolution," Zeidan said.
Cameron highlighted the two countries' shared interest in boosting security in Libya. He cited cooperation on investigations into the 1988 Lockerbie airplane bombing and the 1984 shooting of police officer Yvonne Fletcher outside the Libyan embassy in London.
Cameron said police investigating the 1988 bombing of a PanAm flight over the Scottish town which killed 270 people had been granted permission to visit Libya.
"I am delighted that the Dumfries and Galloway police team will be able to visit your country to look further into the issues around the Lockerbie bombing," he said.
Cameron said Britain's Metropolitan police had travelled to Libya three times as part of investigations into Fletcher's murder, who was 25 when she was hit by a shot fired from the embassy during an anti-Gaddafi demonstration. Such trips would have been "unthinkable" under the Gaddafi regime, he said.
"In all these cases what I want to achieve is justice and also the full uncovering of all the facts." (Reporting by Marie-Louise Gumuchian; additional reporting by Adrian Croft in Brussels; Writing by Mohammed Abbas in London; Editing by Stephen Powell)