BANGKOK, Feb 27 (Reuters) - Southeast Asian stock markets gained on Thursday, with Indonesia up on selective buying in shares with good dividend yields, but investors across the region were largely on the defensive ahead of the U.S. Federal Reserve chairman's testimony on the Fed monetary policy plan. Asian shares struggled to find a solid footing on Thursday as escalating tensions in Ukraine sent investors scurrying to the safety of the dollar and U.S. Treasuries. Jakarta's Composite Index was up 0.4 percent, led by shares of Bank Negara Indonesia and Bank Mandiri , among attractive dividend-yielding stocks. Indonesia had come under selling pressure over the past three sessions amid profit taking after the market rallied to a five-month high last week and on caution ahead of trade data for January, due out next week. "We expect January trade balance to remain surplus, albeit much smaller than $1.5 billion in December. We suggest investors to start buying on weakness as we think downside is limited at this point," said a report from Jakarta-based Trimegah Securities. The Thai SET index rose 0.4 percent, with banking shares up 1.3 percent in their dividend announcement week. Fears about the street violence in downtown Bangkok this week and concerns over the political impact on the domestic economy have kept the market in a tight range. "Overall Thailand's economy should continue to show it suffered from political turmoil and the absence of a permanent government," strategists at broker KGI Securities said in a report. Thailand's anti-corruption agency brings charges of negligence against Prime Minister Yingluck Shinawatra on Thursday as anti-government protesters demand her ouster in a standoff marred by violence that shows no sign of coming to an end. Stocks in Singapore, Malaysia, the Philippines and Vietnam posted limited gains as MSCI's broadest index of Asia-Pacific shares outside Japan was up 0.3 percent ahead of Janet Yellen's testimony. For Asian Companies click; For South East Asia Hot Stock reports, click; SOUTHEAST ASIAN STOCK MARKETS Change at 0555 GMT Market Current Prev Close Pct Move TR SE Asia Index* 395.50 394.46 +0.26 Singapore 3094.14 3088.25 +0.19 Kuala Lumpur 1828.88 1822.55 +0.35 Bangkok 1309.34 1304.62 +0.36 Jakarta 4552.04 4532.72 +0.43 Manila 6337.08 6322.60 +0.23 Ho Chi Minh 594.42 589.81 +0.78 * The Thomson Reuters South East Asia Index is a highly representative indicator of stocks listed in Indonesia, Malaysia, the Philippines, Singapore, Thailand and Vietnam.