Singapore shares were slightly down after the European Central Bank disappointed markets by taking no immediate action and only hinted at future steps to tackle the euro zone's fiscal woes.

The Straits Times Index (STI) was 0.1 percent lower at 3,032 points, while MSCI's broadest index of Asia-Pacific shares outside Japan slipped 1 percent.

Citigroup said the STI was trading just above its 12-month forward target of 3,000 points and the index's valuations -- price-earnings ratio of 14.4 times and trailing price-to-book of 1.4 times -- were near the historical mean.

Citi said the stocks it likes include Keppel Corp, Hongkong Land, Noble Group and Neptune Orient Lines. It removed Oversea-Chinese Banking Corp from its top picks, citing limited upside after the bank's strong performance since early June.

Citi said it would trim stocks such as Singapore Airlines , Tiger Airways Holdings, COSCO Corp Singapore and Singapore Exchange.

Shares of Sembcorp Marine, the world's second-largest rig builder, fell as much as 1.4 percent after brokers cut their target prices following the company's 5 percent fall in second-quarter net profit.

1341 (0541 GMT)

(Reporting by Eveline Danubrata in Singapore; eveline.danubrata@thomsonreuters.com)