British Prime Minister David Cameron hopes to discuss the fight against extremism with Chinese President Xi Jinping on a state visit hailed as a landmark by both China and Britain.

Xi and his wife said goodbye to Queen Elizabeth II Thursday after spending two nights at Buckingham Palace. Xi will dine at Cameron's country estate, Chequers, before visiting Manchester to end his four-day trip.

Cameron's office said Thursday's talks would focus on international affairs and how China can help battle extremism.

The high-profile visit has seen the two countries sign more than 30 billion pounds ($46 billion) in trade agreements — and attracted protests.

It has dominated state media in China, where the Communist Party newspaper Global Times said "the Sino-U.K. relationship will expect the harvest of the 'golden era.'"