Image copyright AP

The US Dow Jones stock index has closed at a record high for the 12th day running as Donald Trump promised a "big" infrastructure announcement.

It is the longest winning streak for the share index since January 1987.

Analysts said Wall Street was buoyed by hopes the US president would set out more on his spending and tax plans in a speech to Congress on Tuesday.

The Dow Jones Industrial Average, one of the US's three main stock indexes, finished 15 points higher at 20,837.

Ahead of the speech, Mr Trump said: "We're going to make it easier for states to invest in infrastructure and I'm going to have a big statement tomorrow night on infrastructure."

The president also said he would seek to boost defence spending by $54bn (£43bn), a 10% rise, in his proposed budget plans for 2018.

Trump bump

As well as significantly raising infrastructure spending, Mr Trump has previously pledged to cut taxes for US businesses.

"For the moment, whenever he speaks of those upcoming plans, we get a leg up in the market," Peter Jankovskis, director of research at Oakbrook Investments, told BBC World Service.

"Whenever he's not talking, there's enough momentum to keep it moving forward."

The S&P 500 index also edged two points higher to 2,370, while the tech-focused Nasdaq Composite index rose 17 points to 5,862.

The biggest winners were shares in energy, financial and healthcare firms - areas that stand to gain if Mr Trump's policies spur faster economic growth, Mr Jankovskis said.

The Dow closed at record highs for 13 sessions in a row in January 1987, nine months before the Black Monday market crash.