* European shares open higher
* Euro zone PMI data weaker than expected
* Trump expected to sign bill backing Hong Kong protesters into law
* Asian stock markets: https://tmsnrt.rs/2zpUAr4 (Updates throughout, changes byline, dateline)
By Sujata Rao and Tom Arnold
LONDON, Nov 22 (Reuters) - Global stocks inched up on Friday, lifted by China's renewed offer to work out a trade pact with Washington, but gains were limited by uncertainty over how the 16-month-old trade war plays out and how much it may undermine the world economy.
Such jitters have put MSCI's index of global shares on course to snap a six-week streak of gains, with lacklustre economic data and rising political risks in the United States and Britain also casting a pall on sentiment.
European shares opened modestly firmer, however, rising off three-week lows touched on Thursday when it seemed that U.S. legislation on Hong Kong would undermine planned trade talks between the world's two largest economies. The broader Euro STOXX 600 was up 0.77%.
Wall Street futures too were marked slightly firmer after China said it was willing to work with the United States to resolve core trade concerns, and the Wall Street Journal reported China had invited U.S. trade negotiators for a new round of face-to-face talks in Beijing.
But whipsawing hopes over reaching even a "phase one" deal before tariff hikes kick in on Dec. 15 have restrained markets.
"Markets are being held hostage by news - positive or negative - coming out of the United States or China. Even if the phase one agreement materialises there is no way I would believe that's the end of the story, it will just move to German cars or Japanese exports," said Marie Owens-Thomsen, chief global economist at wealth manager Indosuez.
Concerns linger, with U.S. President Donald Trump expected to sign into law two bills backing protesters in Hong Kong after the U.S. House of Representatives voted 417-1 for the "Hong Kong Human Rights and Democracy Act", which the Senate had passed unanimously a day earlier.
"If he's going to be forced to sign it, then it brings another (element) of uncertainty to this phase one trade deal, which then pushes back into next year," said Matt Simpson, senior market analyst at GAIN Capital in Singapore.
But Simpson said that in the absence of major news on trade, rangebound market moves are "quite reflective of the small headlines coming through".
Chinese blue-chip shares closed 0.82% lower and Asian shares ex-Japan firmed 0.3% after the previous day's steep falls. Yields on U.S. and German government bonds were a shade higher, with 10-year Treasury yields inching up to 1.7774%, up from its U.S. close of 1.772% on Thursday.
The failure to resolve the trade spat means the world economy is struggling to recover from its slowdown and the Organisation for Economic Cooperation and Development on Thursday forecast growth at a decade-low 2.9% this year and the next.
That fragility was underscored by weaker than expected data showing Euro zone business growth almost ground to a halt this month as activity in the dominant services industry increased at a much weaker pace than expected.
IHS Markit's flash composite Purchasing Managers' Index, seen as a reliable guide to economic health, was 50.3, down from October's 50.6 and moving towards the 50 mark that separates growth from contraction.
In currency markets, the euro dipped into negative territory against the U.S. dollar after the release of the PMI data.
Against a basket of currencies,, the dollar was down less than 0.1%, breaking its three-day streak of gains and heading for its smallest weekly change since the start of August.
Oil prices retreated after hitting two-month highs following a Reuters report that the Organization of the Petroleum Exporting Countries and its allies are likely to extend existing output cuts until mid-2020. [nL8N2803W0. Global benchmark Brent crude was down 0.31% at $63.77 per barrel.
Spot gold edged up 0.2% to $1,467.26 per ounce. (Additional reporting by Andrew Galbraith; Editing by Lincoln Feast and Mark Heinrich)