By Sneha Kumar

April 2 (Reuters) - Emerging Asian equities and currencies tumbled on Thursday after U.S. President Donald Trump threatened to keep hitting Iran and spooked investors who had been betting on a fast resolution to the war.

The MSCI gauge of EM Asia equities .MIMS00000PUS stumbled 2.3%, while the currency index .MIEM00000CUS eased 0.2%. South Korea's KOSPI index .KS11 plunged 4.2% after rising as much as 1.8% earlier in the day.

In a prime-time address, Trump warned that the U.S. would strike Iran "extremely hard" within weeks, claiming military goals were nearly met but stopping short of any timeline for ending the conflict.

"The statement led caution to set in again as Trump doubled down on his stance, without providing clarity on any potential signs of resolution," said Lavanya Venkateswaran, senior ASEAN economist, OCBC.

"The conflict is not ending in the near-term and that real economic pressures continue to build."

Shares in Singapore .STI opened at a two-week high before falling 0.8%, while Malaysia's benchmark stock index .KLSE dropped 1%. Equities in Indonesia .JKSE and Taiwan .TWII declined around 1% and 1.4%, respectively.

"Two or three weeks (of the war) could prove challenging for economies in this region considering the incoming fuel shipments through the Straits of Hormuz are only trickling in on a selective basis," said Venkateswaran.

Most Southeast Asian countries rely heavily on oil imports, leaving them especially exposed to the sharp rise in oil prices triggered by the Middle East war.

Higher energy costs risk widening trade deficits, slowing growth, and stoking inflation, while prolonged supply-chain disruptions could critically drain national energy reserves.

Brent crude futures LCOc1 jumped about 5% after Trump's speech, while the dollar index =USD rose 0.4%.

While the Philippine peso PHP= slipped as much as 0.7% to 60.614 per U.S. dollar, the South Korean won KRW=KFTC slid past the 1,520 level to remain the region's most battered currency.

Indonesia's rupiah IDR= depreciated 0.2%, erasing the marginal gains made in the previous session amid persistent investor concerns over the country's fiscal deficit, central bank autonomy and governance issues.

Faring slightly better than most of their peers, the ringgit MYR= and the Taiwan dollar TDW=TP remained largely unchanged.

The Indian rupee INR=IN rose sharply to 93.53 against the U.S. dollar in early trade after the central bank's latest measures to support the note.

The Philippine stock market was closed for a holiday.

HIGHLIGHTS:

** Yield on Indonesia's 10-year bonds ID10YT=RR rises to 6.708%

** Indonesia earthquake damages buildings, triggers tsunami waves

** South Korea March inflation undershoots forecasts but risks skewed higher

(Reporting by Sneha Kumar in Bengaluru; Editing by Subhranshu Sahu)

((Sneha.kumar@thomsonreuters.com))