Actor Michael Sheen has spent time with Syrian refugees at a large camp in Lebanon but warns that cold weather presents a real threat.
The Government will urge for international action to protect women and girls from violence and sexual exploitation in emergency situations.
The violence in Syria threatens an uneasy truce in neighbouring Lebanon where guns have reappeared on the streets after years of peace.
Eighteen people have now died after explosions near the Iranian embassy in Beirut, Lebanon, a senior medical source has told Reuters.
The explosions, which also wounded dozens, damaged several buildings around the embassy compound.
Seven people have been killed by two explosions near the Iranian embassy in the Lebanese capital Beirut.
At least six buildings have been damaged in the embassy compound, Reuters reported.
Soldiers, policemen and medical personnel gathered at the blast site.
At least seven people have been killed following a car bomb near the Iranian Embassy in Beirut, Lebanon, security officials have told Reuters.
Two Turkish Airlines pilots who were kidnapped in August in Lebanon have been turned over to Lebanese security officials and are expected to fly home later, Turkey's state-run Anadolu Agency said.
Pilots Murat Akpinar and Murat Agca were abducted two months ago by relatives of one of 11 Lebanese hostages taken in May 2012 by opposition fighters in Syria.
Two of those hostages were released previously, and the remaining nine were freed today, paving the way for the Turkish pilots' release.
Turkey is seen as wielding considerable influence over rebels fighting against Syrian President Bashar al-Assad.
The US State Department said it had evacuated non-emergency personnel and family members from its embassy in the Lebanese capital Beirut, as Congress debates a military strike on neighbouring Syria.
"The Department of State drew down non-emergency personnel and family members from Embassy Beirut due to threats to US Mission facilities and personnel," a statement on the Beirut embassy's website said.
Israel has submitted a formal complaint to Britain after the UK ambassador to Lebanon said that Europe's decision to blacklist Hezbollah was not because of its behaviour towards Israel.
Jerusalem claimed that Tom Fletcher's remarks would encourage future attacks on Israeli civilians.
In an interview with Al-Monitor, a Middle East online news source, Mr Fletcher said: "There has been a lot of distortions on that subject .. I invite people to look at the facts: there was an attack inside Europe and it killed people. We do not accept terrorism in Europe."
Mr Fletcher was referring to a bus bombing that killed five Israeli tourists and a Bulgarian driver at the Black Sea city of Burgas in 2012.
The decision to add Hezbollah to the European Union terror list last month was because of this attack, he said.
The Foreign Office has said Britons should avoid all but essential travel to Lebanon as there "may be a heightened risk of anti-Western sentiment" in the country.
A spokesman added: "The UK remains strongly committed to Lebanese stability and will continue to implement a $120 million stability package, including humanitarian support and capacity building with the Lebanese armed forces.
"There may be a heightened risk of anti-Western sentiment in certain countries linked to the possibility of military action in Syria. We advise UK nationals to be vigilant, to avoid any protests or demonstrations and to keep up to date with developments."
Britons should avoid all but essential travel to Lebanon amid a "heightened risk of anti-Western sentiment in certain countries linked to the possibility of military action in Syria", the Foreign Office said.
A suspect has been arrested following the double bombing in Tripoli which killed at least 42 people, according to AP.
Sheik Ahmad al-Ghareeb, who is said to have Sunni ties, appeared in surveillance footage at the site of one of the explosions.
The explosions, which appeared to be coordinated, went off outside two mosques as Friday prayers ended.