* Trump's tariffs come into force * Philippines, Indonesia, Malaysia down By Nikhil Subba May 10 (Reuters) - Indonesian stocks fell the most after hopes of an imminent interest rate cut dimmed, with most others in Southeast Asia remaining subdued on Friday, as U.S. tariffs on Chinese imports kicked in while the two nations engage in crucial talks to rescue a trade deal. U.S. President Donald Trump said on Thursday he believed it was possible to reach a deal this week after he received a "beautiful letter" from Chinese President Xi Jinping which called for the two nations to work together to reach a possible agreement. However, Xi's overtures failed to avert U.S. levies, as Trump's tariff increase to 25 percent on $200 billion worth of Chinese goods took effect on Friday, ratcheting up tensions between the United States and China. China has vowed to retaliate. "Most of the concerns related to the U.S.-China trade war have been largely factored in for now. Markets are trying to figure out what the new development from the U.S. would be," said Taye Shim, head of research at Mirae Asset Sekuritas. Singapore's Straits Times index rose 0.1%, boosted by financial stocks. The index has fallen 3% since Monday, and is set for its worst week since Oct. 12, 2018. DBS Group, the largest lender in Southeast Asia, slipped about 0.9%, while United Overseas Bank fell 1.3%. Vietnamese stocks inched up 0.3%, buoyed by financials and energy stocks. The index is poised to have its worst week since December 2018. Malaysian stocks shed 0.3%, while Indonesia fell 0.3%, dragged by basic materials and financials. Indonesia's current account deficit narrowed in January-March to the smallest in a year, helping the country to post a balance of payments surplus, but some economists say this would not trigger an interest rate cut by the central bank. The Indonesian market is also a little concerned that President Joko Widodo might have to spend more time on politics than reforming policies, Shim said. The incumbent president won an April 17 election based on sample counts of votes by private pollsters, but official results are due on May 22. Philippine stocks fell 0.2%, led by energy stocks. The benchmark is set for its biggest weekly loss since March 1. The archipelago's central bank on Thursday cut its benchmark interest rate by 25 basis points to 4.50 percent on Thursday to support economic growth, which faltered in the first quarter. For Asian Companies click; SOUTHEAST ASIAN STOCK MARKETS AT 0350 GMT Market Current Previous Pct Move close Singapore 3273.74 3269.7 0.12 Bangkok 1641.31 1646.8 -0.33 Manila 7740.09 7755.62 -0.20 Jakarta 6178.132 6198.804 -0.33 Kuala Lumpur 1613.61 1618.53 -0.30 Ho Chi Minh 949.44 947.01 0.26 Change on year Market Current End 2018 Pct Move Singapore 3273.74 3068.76 6.68 Bangkok 1641.31 1563.88 4.95 Manila 7740.09 7466.02 3.67 Jakarta 6178.132 6194.498 -0.26 Kuala Lumpur 1613.61 1690.58 -4.55 Ho Chi Minh 949.44 892.54 6.38 (Reporting by Nikhil Subba; Editing by Shreejay Sinha)