US close: Nasdaq clinches record close despite lingering geopolitical tensions

US stocks closed higher on Wednesday despite news that Iran had fired rockets at two Iraqi bases hosting American troops, albeit without killing any servicemen.

At the close, the Dow Jones Industrial Average was up 0.56% at 28,745.09, while the S&P 500 was 0.49% firmer at 3,253.05 and the Nasdaq Composite saw out the session 0.67% stronger at 9,129.24 - a new record high for the index.

The Dow closed 161.41 points higher on Wednesday after ending the session lower a day earlier as investors continued to monitor headlines surrounding tensions in the Middle East.

Sentiment took a blow late on Tuesday after reports that the Al-Assad airbase in Western Iraq had been struck by multiple projectiles.

The Pentagon later confirmed the report, stating: "Iran launched more than a dozen ballistic missiles against US military and coalition forces in Iraq. It is clear that these missiles were launched from Iran and targeted at least two Iraqi military bases hosting US military and coalition personnel at Al-Assad and Irbil."

President Donald Trump tweeted: "All is well! Missiles launched from Iran at two military bases located in Iraq."

"Assessment of casualties & damages taking place now. So far, so good! We have the most powerful and well-equipped military anywhere in the world, by far!"

However, stocks fell from session highs near the end of trading following unconfirmed reports of an explosion near Baghdad's Green Zone.

The news came shortly after Trump said Iran appeared to be "standing down" after its attack on the Ain al-Asad airbase overnight but added the US would "immediately impose additional punishing economic sanctions on the Iranian regime".

On the data front, private-sector employment in the US rose more than expected in December, according to figures released by ADP on Wednesday.

Employers added 202,000 jobs last month versus expectations of a 160,000 increase. Meanwhile, the November total of jobs was revised up to 124,000 from 67,000.

In corporate news, Boeing shares were down 1.75% at the close after a 737 airliner burst into flames shortly after takeoff, killing all 176 people on board, while shares in pharmacy chain Walgreens Boots Alliance were down 5.84% after earnings fell short of Wall Street expectations.