HANOI - Vietnam’s top real estate firm Vingroup said on Monday it is planning a resort island project off the northern port city of Hai Phong - a project whose worth state-run media has put at about 19 trillion dong ($870 million). Vingroup did not say whether it would be the sole investor or would bring in others. It is also planning billions of dollars of investment in other retail and property projects around the country. The five-year project will include villas, a golf course, an entertainment park, an eco-park and a cable car service in an area of more than 870 hectares (2,150 acres) on Vu Yen island, Vingroup said in a statement. A government news website reported that city authorities also want to add a casino, a five-star hotel, and a marina to the project. The golf course is due to begin operations in early 2016, it said. Shares of Vingroup fell 0.5 percent on Monday, compared to rises for most Vietnamese blue-chips.