SINGAPORE, June 17 (Reuters) - Malaysian palm oil futures fell for a second straight day on Thursday, as it tracked cheaper rival oils and as improved demand prospects from India faded, although a weaker ringgit limited some losses.

The benchmark palm oil contract for September delivery on the Bursa Malaysia Derivatives Exchange fell 21 ringgit, or 0.6%, to 3,384 ringgit ($819.97) a tonne.

"Palm is down because of external markets," a Kuala Lumpur trader told Reuters.

Soyoil contract on the Chicago Board of Trade (CBOT) fell 0.4%. U.S. soybean futures fell for a seventh consecutive session on Thursday as a strong dollar pushed prices to a two-month low.

Soybean oil prices on the Dalian Commodity Exchange meanwhile dropped 1.5%, while its palm oil contract fell 1.6%.

Palm oil is affected by price movements in related oils as they compete for a share in the global vegetable oils market.

Prices were also affected by lower demand from India, which announced on Wednesday that it will not lower import duties, as widely expected.

A weaker ringgit, which fell 0.3% against the dollar however, limited the losses, as it made the edible oil more attractive to holders of foreign currency.

Palm oil may break a support at 3,351 ringgit per tonne and fall to 3,195 ringgit, Reuters analyst Wang Tao said. DATA/EVENTS (GMT) 0900 EU HICP Final MM, YY May 1230 US Initial Jobless Clm Weekly 1230 US Philly Fed Business Indx June (1 liked) ($1 = 4.1270 ringgit)

(Reporting by Fathin Ungku; Editing by Shailesh Kuber)