* Indian rupee declines the most
* Korean won, Taiwan dollar firms in catch-up mode
* Indonesian rupiah set for worst session in over 1 month (Adds text, updates prices)
By Shreya Mariam Job
Sept 16 (Reuters) - Most Asian currencies weakened against the dollar on Monday, with net oil-importers taking a sharp hit after an attack on Saudi Arabia's oil facilities drove up crude prices and worsened tensions between the United States and Iran.
Oil prices soared with Brent crude posting its biggest intra-day percentage gain since the Gulf War in 1991, after an attack on Saudi Aramco's crude processing sites on Saturday shut about 5% of global supply.
"Emerging Asian currencies most at risk to higher oil prices belong to countries with the largest oil trade deficits. They are the South Korean won, the Thai baht and the Indian rupee," a DBS note said.
The Indian rupee was the worst hit by the surge in oil prices, weakening 0.9%, while the Indonesian rupiah shed 0.6%, its biggest intraday percentage drop since Aug 6.
Also adding to pressure, Indonesia's exports fell 9.99% in August, sharper that a Reuters poll prediction of a 6% fall.
The Philippine peso weakened 0.5% against the dollar, while the Thai baht edged lower.
Meanwhile, U.S. President Donald Trump's comments that the United States was "locked and loaded" for a potential response to the attack spiked U.S.-Iran tensions and further strained risk appetite.
Investors now await the U.S. Federal Reserve rate decision expected later this week with the market expecting a rate cut for the second meeting in a row.
Malaysian financial markets were closed for a holiday.
WON AND TAIWAN DOLLAR PLAY CATCH UP
The Taiwan dollar and the South Korean won firmed 0.4% and 0.6%, respectively, catching up on an Asian currency rally on Friday, when both markets were closed.
"Taiwan and Korea were both closed so they are both on a catch-up mode as far as the risk-on sentiment is concerned," Eugenia Victorino, head of Asia strategy at Skandinaviska Enskilda Banken said.
However, she added the spike in risk aversion from the Aramco attack would now limit that upside for both currencies.
The following table shows rates for Asian currencies against the dollar at 0525 GMT.
CURRENCIES VS U.S. DOLLAR Change on the day at 0525 GMT
Currency Latest bid Previous day Pct Move Japan yen 107.820 108.07 +0.23 Sing dlr 1.373 1.3731 -0.01 Taiwan dlr 30.942 31.055 +0.37 Korean won 1184.100 1191 +0.58 Baht 30.460 30.41 -0.16 Peso 52.270 51.99 -0.54 Rupiah 14040.000 13960 -0.57 Rupee 71.535 70.92 -0.87 Yuan 7.071 7.0788 +0.11
Currency Latest bid End 2018 Pct Move Japan yen 107.820 109.56 +1.61 Sing dlr 1.373 1.3627 -0.76 Taiwan dlr 30.942 30.733 -0.68 Korean won 1184.100 1115.70 -5.78 Baht 30.460 32.55 +6.86 Peso 52.270 52.47 +0.38 Rupiah 14040.000 14375 +2.39 Rupee 71.535 69.77 -2.47 Ringgit 4.163 4.1300 -0.79 Yuan 7.071 6.8730 -2.80