European markets opened lower on Friday as market participants exercised caution ahead of a crucial US Federal Reserve meeting, where the central bank could announce a reduction in its $85bn a month asset-buying stimulus.

The Stoxx Europe 600 index opened 0.2% lower to 310.06.

Britain's FTSE 100 and France's CAC 40 opened 0.2% lower .

Germany's DAX 30 opened 0.3% lower.

Spain's IBEX 35 was down 0.32% in early trade.

Italy's FTSE MIB was down 0.37% in early trade.

The Fed's policy-setting committee will meet on 17-18 September. Market participants expect the central bank to provide clarity on the timing and size of the planned reduction of its monthly bond purchases.

"The key question market participants are asking is by how much will the US Federal Reserve taper? And the answer seems to be somewhere around $10bn, effecting only longer term US treasury purchases, and not mortgage backed securities," said Tim Radford, global analyst at Rivkin Securities.

Meanwhile, in Geneva, US Secretary of State John Kerry is expected to continue discussing the Syrian crisis with Russian Foreign Minister Sergei Lavrov on 13 September. The two sides are trying to explore a diplomatic solution to the ongoing crisis.

Earlier, Syrian President Bashar al-Assad confirmed his government was willing to give up its chemical weapons stockpiles. Appearing on a Russian television channel, Assad said he was ready to place his chemical arsenal under international control.

In the UK, the chief of the Communications Workers Union alleged that the government's decision to privatise the Royal Mail is down to cronyism. His reaction followed the news that the Royal Mail will be floated on the London Stock Exchange within weeks.

In company news, micro-blogging site Twitter announced that it has filed for an initial public offering (IPO) to take the company public. The firm tweeted: "We've confidentially submitted an S-1 to the SEC for a planned IPO. This Tweet does not constitute an offer of any securities for sale." Goldman Sachs is the lead underwriter for the IPO, reported CNBC.

In Asia and the US

In Asia, the Japanese Nikkei finished 0.12% higher on 13 September. Australia's S&P/ASX closed 0.44% lower while South Korea's Kospi ended 0.49% lower.

Earlier in Asia, most markets traded lower as caution set in ahead of the Fed's FOMC meeting,

In India, government data released on 12 September showed that industrial production bounced back in July just as consumer inflation eased in August, offering a much needed respite for the government. Industrial output rose 2.6% from a year ago, while retail inflation eased to 9.52% in August from 9.64 in the preceding month.

Earlier, Japanese media reports said the government is considering options including a 5tn yen ($50bn, €38bn, £32bn) spending package to cushion the planned sales tax hike.

On Wall Street, indices ended lower on 12 September, ahead of the key Fed meeting. "US stocks fell but declines were limited as investors took a break after seven consecutive sessions of gains," Radford said.

The Dow finished 25.96 points lower at 15,300.64, pulled down by JPMorgan and DuPont.

The S&P 500 closed 5.71 points lower at 1,683.42 while the Nasdaq ended 9.04 points lower at 3,715.97.

Government data released on 12 September showed that the number of Americans filing new claims for government-funded jobless benefits dropped to a more than seven-year low.

However, the latest and last major reading of the US labour market, ahead of the FOMC meeting, should be viewed with scepticism -- technical issues prevented two states from processing all the claims they received during the week ended 7 September, reported Reuters.

Despite the unprocessed claims, the data suggested the US labour market was on the recovery path and this could influence the Fed's monetary stimulus decision, expected on 18 September.