Europe's stock markets wavered on Wednesday as investor caution prevailed before the Federal Reserve's latest interest rate call.

Frankfurt equities sagged despite a rally for shares in German heavy industry giant ThyssenKrupp, which announced a deal with Indian group Tata to merge their steel operations in Europe.

Thyssenkrupp jumped 3.37 percent to stand at 26.10 euros in Frankfurt midday deals following news of the combination to create Europe's second-largest steelmaker after ArcelorMittal, whose stock was up 0.76 percent at 22.52 euros in Paris.

The main index in the French capital edged lower overall, but London held firm as official data revealed an August surge in British retail sales.

Asian equities earlier moved tentatively after US President Donald Trump threatened to "totally destroy" North Korea if it threatened the US or its allies.

Focus was switching to 1800 GMT when the US Federal Reserve announces the outcome of its latest monetary policy meeting.

"The Fed trumps all else, and with hours to go until the next decision, caution reigns supreme," said IG analyst Chris Beauchamp.

"Today's Fed meeting provides us with enough to pore over for weeks to come.

"Details on balance sheet reduction will be of interest, but crucially the committee will extend its rate outlook in 2020, and this could give us a good sense of the end-point for the interest rate in this current tightening cycle," he added.

A third successive record performance on Wall Street, fanned by speculation about Trump's economic agenda, was not enough to induce much buying elsewhere.

Foreign exchange markets saw little movement, although the Mexican peso was down after an earthquake killed more than 200 people.

While Fed policymakers are not expected to raise interest rates, the post-meeting statement and comments from chair Janet Yellen are the main focus as traders hope for a timetable on winding down its crisis-era bond-buying stimulus.

Wednesday's announcement comes amid broader moves by global central banks to tighten monetary policy in the face of rebounding world economic growth, dealers said.

- 'Money is still cheap' -

"We expect steady Fed policy through to the end of the year," Rabobank analyst Jane Foley told AFP.

"All central banks would like to regain more ammunition in preparation of the next downturn, so in this context there is a universal desire of central banks to have higher interest rates -- but not at any cost clearly."

She added: "When the low levels of bond yields is taken into account, money is still very cheap. This factor, combined with good levels of global growth, is a good environment for stocks."

- Key figures around 1045 GMT -

London - FTSE 100: UP 0.1 percent at 7,279.47 points

Frankfurt - DAX 30: DOWN 0.1 percent at 12,555.57

Paris - CAC 40: UP 0.1 percent at 5,243.47

EURO STOXX 50: DOWN 0.1 percent at 3,528.11

Tokyo - Nikkei 225: UP 0.1 percent at 20,310.46 (close)

Hong Kong - Hang Seng: UP 0.3 percent at 28,127.80 (close)

Shanghai - Composite: UP 0.3 percent at 3,366.00 (close)

New York - DOW: UP 0.2 percent at 22,370.80 (close)

Euro/dollar: UP at $1.2007 from $1.1994 at 2100 GMT

Dollar/yen: DOWN at 111.36 yen from 111.60 yen

Pound/dollar: UP at $1.3566 from $1.3521

Oil - Brent North Sea: UP 48 cents at $55.62 per barrel

Oil - West Texas Intermediate: UP 56 cents at $50.04

Source: AFP