Airbus Helicopters said Friday has signed a letter of intent for the sale of 100 H135 helicopters to China and the construction of an assembly plant there.

The 750 million euro ($800 million) deal for the versatile twin engine machines often deployed in emergency medical services came as German Chancellor Angela Merkel visits the Asian giant.

European manufacturer Airbus Helicopters has a 40 percent market share of a Chinese market, and believes the country has a 20-year demand of up to 5,000 copters.

The helicopters will be helicopters locally at the Sino-German ecopark development in Qingdao, in eastern Shandong province, Airbus Helicopters said.

The firm dubbed the accord a "major step forward for Airbus Helicopters in China", seeing the country as having become its important market globally.

The agreement "consolidates its position as the leading helicopter manufacturer in the Chinese market," Airbus Helicopters added in a statement.

The deal came a day after an accord between Airbus and state-owned China Aviation Supplies Holding Group for 100 A320 aircraft, worth $9.7 billion at list prices.

They also confirmed 30 options for twin-aisle A330s, among a 75-plane deal announced in June ahead of a visit by Li to Airbus headquarters in the French city of Toulouse.

Airbus -- which has an aircraft assembly facility in the northern Chinese port of Tianjin -- is engaged in a fierce struggle with its US rival Boeing for dominance in the crucial Chinese market.

China is also developing its own fledgling aerospace industry even as it ramps up deals with foreign manufacturers.