A 7.4-magnitude earthquake has struck off the coasts of Argentina and Chile, sparking tsunami warnings. The quake was registered 219km (136 miles) south of Ushuaia, Argentina, according to the US Geological Survey (USGS). It struck between Cape Horn and Antarctica at a depth of 10km (six miles) at around 9am local time (1pm UK time), the USGS confirmed. Four further tremors ranging from 5.4 to 5.7 in magnitude have hit the same area off Argentina since. Chilean authorities have issued a tsunami warning for the coastal Magallanes region in the south of the country. People were urged to "act calmly and follow the instructions of the authorities". The country's president, Gabriel Boric, wrote on X that "all resources are available" to respond to potential emergencies. It comes after a magnitude 5.83 tremor struck Argentina's La Rioja province on Thursday, according to the German Research Centre for Geosciences. This breaking news story is being updated and more details will be published shortly. Please refresh the page for the fullest version. You can receive Breaking News alerts on a smartphone or tablet via the Sky News App. You can also follow @SkyNews on X or subscribe to our YouTube channel to keep up with the latest news.