* Investors await U.S.-China trade deal signing on Jan. 15
* Chinese stocks end lower as traders book profits
* Russian rouble slips on state FX intervention
* Turkish lira down ahead of central bank meeting
* South Africa's rand slides on low consumer confidence
Jan 14 (Reuters) - Emerging market stocks idled near 19-month highs on Tuesday in the run-up to an expected signing of an initial U.S.-China trade deal this week, while the Russian rouble was weighed down by the state's foreign currency purchases.
An index of emerging market equities was flat at 0850 GMT, after gaining for three straight days on an easing in U.S.-Iran tensions and optimism around the Phase 1 Sino-U.S. trade agreement.
Chinese stocks ended Tuesday's session about 0.3% lower as traders booked profits after the recent rally.
But global stocks hovered near record highs, with the world's attention squarely on the trade pact between Washington and Beijing that is due to be signed on Wednesday.
"The fact that markets have priced in the signing tomorrow does leave an opening for downside risks if there is any disappointment," said Trieu Pham, emerging market debt strategist at ING.
"But for now, investors are taking an optimistic stance."
In signs of increasing goodwill between the world's top two economies, the U.S. Treasury Department on Monday dropped its designation of China as a currency manipulator - a label it had applied as the yuan dropped in August.
While the broader optimism revived demand for emerging market assets towards the end of 2019, a recent Reuters poll found currencies in the region will again cede ground to the dollar this year as a global economic recovery remains fragile at best.
Developing economies are also grappling with political unrest and faltering growth at home, which has prompted many central banks to slash interest rates in an effort to boost inflation.
The Turkish lira eased 0.4%, ahead of a central bank meeting on Thursday. Economists are split between those who expect another interest rate cut at the meeting and those who see no change after the central bank halved the rate last year.
The Russian rouble fell about 0.3% versus a steady dollar. The ministry said on Monday it would increase its daily purchases of foreign currency to the equivalent of 18.2 billion roubles (about $300 million) over the next month.
South Africa's rand tumbled more than half a percent in its fourth straight day of declines.
A survey on Tuesday showed consumer confidence in Africa's most industrialised economy remained at a near two-year low in the fourth quarter, as the country struggles with prolonged power cuts and choppy economic growth.
For GRAPHIC on emerging market FX performance in 2020, see http://tmsnrt.rs/2egbfVh For GRAPHIC on MSCI emerging index performance in 2020, see https://tmsnrt.rs/2OusNdX
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For RUSSIAN market report, see (Reporting by Sagarika Jaisinghani in Bengaluru, Editing by William Maclean)