European stock markets rose, helped by speculation that US President Donald Trump will defer a tariffs decision on European-made cars in a speech later Tuesday.

"Speculation that President Trump will defer making a decision whether to slap tariffs on EU vehicle imports this week has boosted sentiment in European equity markets," said David Madden, analyst at CMC Markets UK. 

"The Trump administration has softened its stance in relation to the EU in recent months, which has been a factor in the rally in European stocks."

After postponing such measures in May, Trump was to decide by mid-November whether to impose the supplementary tariffs on cars built in EU countries -- a step particularly feared by big German automakers.

The outgoing president of the European Commission Jean-Claude Juncker last week said he believed the US would not impose new tariffs on imported European cars in the coming days.

On Wall Street, equities also ticked higher at the opening, with analysts also reporting hopes for a softer Trump stance on trade with China when he speaks at the New York Economic Club at 1700 GMT.

"The markets continue to focus on the recently increased optimism regarding a US-China 'phase one' trade agreement," Charles Schwab analysts said.

Earlier in Asia, Hong Kong's main stocks index closed up 0.5 percent after heavy losses.

Traders moved cautiously, however, after stocks plunged more than two percent Monday when the city was wracked by some of the worst violence seen during months of protests, with one person shot and another set on fire.

The city remains on edge -- with sporadic protests taking place on Tuesday -- while the US expressed "grave concern" over the situation in Hong Kong and called for restraint by security forces and protesters.

"It is still very unclear what can de-escalate the situation," said National Australia Bank's Tapas Strickland.

"Nevertheless, for as long as Beijing gives Hong Kong latitude to deal with the protests, it is likely the unrest will only have an isolated impact on financial markets."

In foreign exchange deals Tuesday, the pound retreated against the dollar a day after winning support from news that the Brexit party would not run against UK Prime Minister Boris Johnson's Conservatives in hundreds of seats at next month's general election.