Britain is sending two Royal Navy ships to the Middle East amid contingency planning for a possible evacuation of British nationals from Lebanon.
The Ministry of Defence said the aircraft carrier HMS Illustrious and the assault ship HMS Bulwark were being sent to the region as the conflict escalates.
But a ministry spokeswoman stressed, "They have been given no specific tasking and this is simply a prudent part of our contingency planning."
HMS Illustrious is currently in Gibraltar and HMS Bulwark is close to Barcelona in Spain.
"There are approximately 3,500 to 4,000 British families registered in Lebanon. There are also 10,000 dual nationals," a Foreign Office spokesman said.
"We are advising people to stay put but to get ready for departure at short notice if necessary. We are in regular contact with our European Union partners," he added.