* Trump plans "significant" tariffs on China
* Turkish lira on track for worst week since 2008
* Emerging market borrowing costs at 18-months high
By Karin Strohecker
LONDON, June 15 (Reuters) - Rattled by trade war fears and steep dollar gains, emerging markets ended the week on a sour note with stocks slipping to more than two-week lows and a clutch of currencies on track for their worst week in years.
MSCI's emerging market stocks benchmark fell 0.8 percent on a third day in the red, with Chinese mainland stocks suffering while export-heavy South Korea slipped 0.8 percent.
Markets were spooked the heightening prospect of a trade war after a U.S. administration official said President Trump had made up his mind to impose "pretty significant" tariffs on Chinese goods.
Beijing said it was ready to respond if Washington chose to ratchet up trade tensions.
Trump is due to unveil revisions to his initial tariff list targeting $50 billion of Chinese goods on Friday, while a second list of tariffs on $100 billion in Chinese goods is nearly completed.
Emerging assets had already suffered on Thursday, digesting Wednesday's hawkish outlook from the U.S. Federal Reserve with the dollar racing higher after the European Central Bank signalled on Thursday it would keep interest rates at record lows up to at least mid-2019.
The dollar's index against a basket of six major peers rose 0.3 percent to 95.111, its highest level since November, after rallying more than 1 percent the previous day.
"The tightening impact on financial conditions of the stronger dollar doesn't help and I think that is at the centre of all the crises we are now talking about in emerging markets," said Jim McCaughan, CEO of $450 billion asset manager Principal.
He expected the dollar to continue go "somewhat higher".
Turkey, which with its large external financing need took centre stage in a recent emerging markets selloff, saw its lira weaken 0.5 percent in a fifth straight day of losses, putting the currency on track for its worst week since the height of the 2008 financial crisis.
Mexico's peso, a lightning rod for trade sentiment across emerging markets, extended Thursday's tumble to weaken 0.2 percent - its weakest level in 18 months. The peso is on track for its worst week since 2015.
China's yuan fell to a near two-week low against the dollar after the central bank in Beijing fixed the official midpoint at the lowest in five months.
Russia's rouble slipped 0.4 percent ahead of a central bank decision. Policymakers are expected to keep rates unchanged despite inflationary pressures following U.S. sanctions.
South Africa's rand bounced 0.5 percent, clawing back half of Thursday's losses.
Borrowing costs across emerging markets stayed at their highest in 18 months.
The premium demanded by investors to hold emerging market hard-currency debt over safe-haven U.S. Treasuries as measured by the J.P.Morgan EMBI Global Diversified index has widened 13 basis points (bps) to 356 bps from last Friday's close.
For TOP NEWS across emerging markets
For CENTRAL EUROPE market report, see
For TURKISH market report, see
For RUSSIAN market report, see) (Reporting and graphic by Karin Strohecker, additional reporting by Marc Jones; editing by John Stonestreet)