1. Global stocks slips

U.S. stock market futures pointed to a lower open on Tuesday morning, as a risk-averse mood spread through the market ahead of an upcoming meeting between U.S. President Donald Trump and Chinese President Xi Jinping.

The blue-chip Dow futures lost 55 points, or around 0.3%, by 09:55 GMT, the S&P 500 futures shed 8 points, while the tech-heavy Nasdaq 100 futures slumped 18 points.

In Europe, stocks were mostly lower in subdued mid-morning trade, with Germany's DAX down around 0.1%, while London's FTSE 100 increased 0.1%.

Earlier, in Asia, markets ended in negative territory, with Japan's Nikkei dropping around 0.9%. The Shanghai Composite in China was closed for a public holiday.

2. Trump-Xi meeting awaited

The main focus for markets this week centers on President Donald Trump's first meeting with Chinese counterpart Xi Jinping on Thursday and Friday.

Last week, Trump tweeted that the meeting, which is expected to cover differences over trade and North Korea, "will be a very difficult one."

That has kept investors on edge, ditching riskier assets, such as stocks, and forcing investors to seek shelter in safe-haven assets such as the JPY, Gold and U.S. Treasuries.

Adding to market jitters was a deadly attack by a suspected Islamic suicide bomber on a metro train in St. Petersburg, Russia on Monday, that killed 14 people and injured about 50.

3. U.S. trade data ahead

U.S. trade deficit data is scheduled for release Tuesday at 12:30 GMT, Economists expect it to have narrowed in February to $44.8 billion from a five-year high of $48.5 billion a month earlier.

Investors will parse through the figures for hints on what it means for trade partnerships with China and other countries amid concern over the Trump Administration's protectionist policies.

Also on the data front, factory orders are scheduled for release at 14:00 GMT.

4. South African currency tumbles

Focus in the currency markets on Tuesday is directed mostly toward the South African rand, which sank to its weakest in almost five months.

The decline came after ratings agency S&P cut the country's credit rating to junk with a negative outlook in wake of last week's surprise dismissal of the country's finance minister, Pravin Gordhan.

The rand fell by as much 2% against the dollar in response to the news of the downgrade, hitting 13.946, a level not seen since November 1. It was last at 13.783 (USD/ZAR).

The South African 10-year bond yield briefly spiked to 9.205%, before falling back to 9.025%.