Chinese hotelier Huazhu Group on Monday has agreed to buy the parent company of Germany's Steigenberger hotels for around 700 million euros ($780 million), widening its global reach, both companies said.

The all-cash deal sees one of China's biggest hoteliers acquire Deutsche Hospitality through its wholly owned subsidiary China Lodging Holding Singapore.

Deutsche Hospitality owns five hotel brands, including Steigenberger, whose hotels are often located in historic buildings and are a household name in Germany.

The nearly 90-year-old German group said earlier this year it wanted to increase the number of its hotels worldwide to 250 by 2024, up from 118 today.

"Both Huazhu and Deutsche Hospitality have strong and recognised brands, which we will maintain, while further accelerating their growth," Deutsche Hospitality said in a joint statement.

Huazhu founder and executive chairman Qi Ji added that the purchase would enhance its offerings "in the high-end European hotel market".

"This acquisition is an important milestone in our global growth strategy," he said.

The deal is expected to close in early 2020.

The NASDAQ-listed Huazhu group operates more than 5,000 hotels in China and has recently expanded into Japan and Singapore.