Emerging-market assets retreated sharply after U.S. President Donald Trump shattered hopes for clarity over the duration of the Middle East conflict, while investors also turned their attention to Egypt's looming interest-rate decision.

In a prime-time address, Trump said the U.S. would strike Iran "extremely hard" within weeks - a marked departure from the earlier tone struck by both him and Secretary of State Marco Rubio ahead of the speech.

The shift left investors once again mired in uncertainty over how, and when, the conflict might draw to a close. Equity markets across the emerging world, which had rallied strongly in the previous session, reversed course decisively.

MSCI's emerging markets stocks index .MSCIEF slid nearly 2%, wiping out the week's earlier gains and underscoring the renewed flight from risk.

The Indian rupee INR= was little changed as investors parsed the Reserve Bank of India's decision to bar banks from offering rupee non-deliverable forwards to both resident and non-resident clients. The central bank rate decision is also due next week.

In Mumbai equities .NSESN.BSESN fell more than 1.5%, swept up in the broader global retreat from riskier assets.

"RBI seems quite serious to follow through on new regulations to control INR weakness. As such, we think the chance of relaxation is much lower even as tweaks could still be possible," said Michael Wan, senior currency analyst at MUFG.

"We think the fundamental flow picture for the rupee still points towards FX weakness moving forward", he added. "Further policy changes by RBI and the India government to manage INR weakness could be likely."

Elsewhere Egypt's pound EGP= traded steadily, while stocks were little changed ahead of the central bank's policy decision.

Policymakers are expected to keep rates on hold, as fears of inflation rekindled by the U.S.-Israeli war on Iran have disrupted what had been a carefully telegraphed easing cycle - a reassessment increasingly visible across emerging markets.

In Poland, central banker Przemyslaw Litwiniuk said he did not expect further rate cuts in the coming months, warning that if the Iran conflict exerts a sustained inflationary impact, rate hikes may yet become necessary.

Losses in the zloty EURPLN= were modest, though stocks in Warsaw .WIG20 fell 1%.

Meanwhile, Vietnam emerged as the latest country seeking to insulate local markets from the fallout of the Iran conflict.

A Reuters report said authorities were planning measures to support the stock market, including a proposal to establish a government-backed stabilisation fund.

Stocks in Ho Chi Minh City .VNI were down 0.8%.

In Indonesia, authorities completed stock market reforms requested by index providers, part of a broader effort to rebuild investor confidence in Southeast Asia's largest economy.

-Pranav Kashyap/Reuters