New Zealand earthquake: UK sends search-and-rescue team
A UK search-and-rescue team has been deployed to New Zealand to join the relief effort after the Christchurch earthquake, David Cameron has said.
The prime minister sent the UK's "deepest sympathies" after the deaths of at least 65 people in the tremor at 1251 on Tuesday (2351 GMT on Monday).
He said the UK "stood ready" to help more at this "dark and difficult time".
The Foreign Office said it was "urgently" seeking information about possible British casualties.
During a visit to Kuwait, Mr Cameron said: "There are many people in Britain with ties of friendship or family to New Zealand.
"They will be following events particularly closely and with understandable anxiety.
"I believe I speak on behalf of everyone in our country when I say that we all stand with New Zealand at this moment, at this dark and difficult time."
Mr Cameron said the UK's high commissioner in the country was on her way to Christchurch, and extra consular staff would arrive on Tuesday.
On Tuesday evening he spoke directly to New Zealand Prime Minister John Key.
A Downing Street spokesman said: "They discussed the latest situation on the ground, and the Prime Minister reiterated Britain's sympathies and condolences at this difficult time."
The UK search-and-rescue team, consisting of 62 people and more than nine tonnes of equipment, will arrive in New Zealand on Thursday to provide relief for teams already on the ground.
"It is a long way from the UK to New Zealand and so our team will take a while to get there, but the New Zealand government confirm that assistance is very much required," the Foreign Office said.
Christchurch was still trying to recover from a 7.1-magnitude quake in September, which left two people seriously injured but no fatalities. It caused an estimated $3bn (£1.9bn) in damage.
Although stronger, the previous quake happened in the middle of the night and its epicentre was further away and deeper underground.
In a message of support to Mr Key, the Queen said: "Please convey my deep sympathy to the families and friends of those who have been killed; my thoughts are with all those who have been affected by this dreadful event.
"My thoughts are also with the emergency services and everyone who is assisting in the rescue efforts."
Barnaby Luck, from Haverfordwest in Pembrokeshire, was in a hostel when the disaster hit at 1251 local time (2351 GMT on Monday).
The 29-year-old, who has been travelling in New Zealand since November, said: "It was like someone had got hold of the building and was shaking it back and forwards, so I just jumped under my bunk bed.
"Once it stopped I was really shaken up and went outside. I only realised the magnitude of it when I looked up the street.
"The gable side of a building 100 yards away was completely levelled to the ground and as I made my way into the centre of the town, there was just total devastation."
Backpacker Christopher Ratcliffe, 27, from Sutton Coldfield, West Midlands, was forced to shelter under a desk in a library.
"When I came outside the city looked like a bomb had hit it," he said.
"There was dust and smoke in the air and bits of glass and rubble falling from the tops of buildings. People were walking around covered in blood and in tears - it was just shocking."
Alison Stokes, originally from Birmingham, was at home with her child and father when the earthquake struck.
"The house was picked up like something from The Wizard of Oz and shaken for what seemed like a minute. It was absolutely terrifying," she said.
A state of emergency has been declared in Christchurch and the authorities are warning the death toll is likely to rise.
Emergency teams are now working under floodlights to reach survivors, as relatives keep vigil outside.
The airport is closed, many power and telephone lines have been knocked out, and burst water mains have flooded whole districts.
Britons in New Zealand can telephone the High Commission on 04 924 2898 for assistance, or the Global Response Centre in the UK on 0044 207 008 1500.
The New Zealand High Commission in London is advising New Zealanders in the UK who are worried about friends and family to monitor the government's official websites, media reports and to try to make direct contact.
It also advised those due to travel to Christchurch to contact their airline or travel agent. All other South Island and New Zealand airports are open.
Christchurch is home to almost 400,000 people, and is considered a tourist centre and gateway to the South Island.
New Zealand sits on the Pacific Ring of Fire, a vast area of seismic activity, and records more than 14,000 earthquakes a year, although only about 150 are felt by residents.