Which countries have offered to help and what aid are they providing?
UK
The UK is sending 76 search-and-rescue specialists with equipment and dogs, as well as an emergency medical team, to Turkey.
The UK also says it is in contact with the UN about getting support to victims in Syria.
US
The US is sending two 79-person search-and-rescue teams to assist Turkish officials, according to the White House.
Meanwhile, nearly 100 Los Angeles County firefighters and structural engineers, along with six specially trained dogs, will be sent to Turkey.
Italy
Italy's Civil Protection Agency has offered assistance to Turkey and a firefighting team was preparing to leave from Pisa.
The Italian military has said transport flights will carry equipment as well as health and other personnel.
France
Rescue teams will be dispatched to Turkey from France.
Spain
Spain will send two urban search and rescue teams to Turkey with 85 personnel and a contingent of volunteer firefighters.
The EU
The European Union has mobilised search and rescue teams to help Turkey, while the Copernicus satellite system has been activated to provide emergency mapping services.
At least 13 member countries have offered assistance. The EU said it is also ready to offer help to Syria through its humanitarian assistance programmes.
Russia
Russian rescue teams from the emergencies ministry are preparing to fly to Syria.
Russian military deployed in the country has already sent 10 units comprising 300 people to help clear debris and search for survivors.
The Russian military has set up points to distribute humanitarian assistance.
Turkey has also accepted an offer of support from Russia.
Germany
Germany is preparing deliveries of emergency generators, tents and blankets. It is also prepared to set up camps with water treatment equipment.
Germany has offered to send teams from the THW civil protection agency to Turkey. The group International Search and Rescue Germany was preparing to fly dozens of doctors and rescue experts to Turkey late on Monday.
Austria
Austria has offered to send 84 soldiers from a military disaster relief unit to Turkey.
Poland
Poland is sending Turkey 76 firefighters and eight-trained dogs with equipment.
Greece
Greece is sending Turkey a team of 21 rescuers, two rescue dogs and a special rescue vehicle, together with a structural engineer, five doctors and seismic planning experts in a military transport plane.
Romania
Romania is sending specialised personnel and material to Turkey on two military aircraft.
Croatia
Croatia is sending 40 personnel and 10 dogs, rescue equipment and vans to Turkey.
Japan
Japan is sending a group of about 75 rescue workers to Turkey.
South Korea
South Korea will dispatch a 60-person search and rescue team and send medical supplies to Turkey.
The government also says it is providing an initial $5m (£4.1m) in humanitarian support, and the Gyeonggi provincial government plans to provide $1m (£800,000) in humanitarian assistance.