* Japanese yen rises on Hong Kong protest escalation
* British pound up despite Moody's warning, poor economic data
* Graphic: World FX rates in 2019 tmsnrt.rs/2egbfVh (Updates prices, adds fresh comment)
By Olga Cotaga
LONDON, Nov 11 (Reuters) - The euro held steady against the U.S. dollar on Monday after matching a four-week low earlier as the greenback maintained its gains on optimism that the United States and China would roll back tariffs that have hurt global growth.
Officials from both countries said late last week that a rollback of some tit-for-tat tariffs had been agreed as part of a preliminary deal, that has still to be finalised, aimed at ending their trade war.
Even though that was subsequently denied by U.S. President Donald Trump on Friday, he did not completely rule out a deal and U.S. benchmark Treasuries held above a key support level at 1.9%, buoying the currency.
Moves were slight as traders kept a wary eye on further news on the U.S.-China trade war, and against the safe-haven Japanese yen the dollar fell as market participants reacted to the escalating political confrontations in Hong Kong.
"Market participants have become more cautious over the potential positive impact for global growth from a partial U.S.-China trade deal following comments from President Trump," said Lee Hardman, currency analyst at MUFG.
"Nevertheless, market participants are likely to remain optimistic that the U.S. and China are moving closer to finalizing a partial trade deal by the end of this year," Hardman said.
The euro traded at $1.1026, flat but not far from the Oct. 15 low of $1.10165 it fell to on Friday.
The Japanese currency was last up 0.3% at 108.93 against the dollar.
"The trade resolution is a little positive for the euro," said Stephen Gallo, European head of FX strategy at BMO Capital Markets.
But China is unlikely to ramp up imports from the euro zone, Gallo said, which means the common currency is unlikely to benefit from the fact that the United States and China could decide to end the 16-month long trade war.
"Any bullish reaction in the euro will in our view be a second, third or fourth order response to a resolution of the trade war," Gallo said.
He sees euro-dollar stuck between $1.10 and $1.12, he said.
The index which tracks the dollar against six major currencies was neutral at 98.317, flirting with a four-week high.
The Chinese yuan weakened 0.3% to 7 per dollar in offshore trade on fresh violence in Hong Kong, where police fired live rounds at protesters, with Cable TV and other media reporting at least one person being wounded.
Disappointing economic data also hurt sentiment toward the yuan, as China's producer prices fell the most in more than three years in October, National Bureau of Statistics (NBS) data showed on Saturday, while the country's consumer prices rose at their fastest pace in almost eight years.
The UK's main stock index fell sharply on Monday as a violent day of protest in Hong Kong knocked Asia-exposed financial stocks.
Elsewhere, the British pound was up 0.4% at $1.2825 despite the fact that Moody's warned on Friday it might again cut its rating on Britain's sovereign debt. Its rise also came even as data showed Britain's economy grew at the slowest annual rate in nearly a decade in the third quarter. (Reporting by Olga Cotaga; Editing by Hugh Lawson)