China's economy cooled in the fourth quarter under pressure from faltering domestic demand and bruising U.S. tariffs, dragging growth in 2018 to its lowest level in nearly three decades and pressuring Beijing to roll out more stimulus to avert a sharper slowdown.

Growing signs of weakness in China — which has generated nearly a third of global growth in recent years — are fueling anxiety about risks to the world economy and are weighing on profits for firms ranging from Apple to big carmakers.

Policymakers have pledged more support this year to reduce the risk of massive job losses but have ruled out a "flood" of stimulus like that which Beijing has relied on in the past, which quickly juiced growth rates but left a mountain of debt.