JAKARTA, June 16 (Reuters) - Malaysian palm oil futures plunged 4% on Wednesday, shedding sharp gains from the previous session, dragged down by a fall in soyoil prices on an improved weather outlook for the U.S. Midwest crop belt.

The benchmark palm oil contract for September delivery on the Bursa Malaysia Derivatives Exchange declined 4.01%, to 3,400 ringgit ($825.64) a tonne during midday break on Wednesday.

"Palm oil prices are tracking weakness from external markets," a Kuala Lumpur-based trader said, referring to palm's rival oils on the Chicago Board of Trade(CBOT) and the Dalian Commodity Exchange.

Soyoil contract on the CBOT dipped 0.96%. Soybean oil prices on the Dalian dropped 0.71%, while its palm oil contract rose 0.03%.

Anilkumar Bagani, research head of Mumbai-based vegetable oils broker Sunvin Group, said dragging the price is also lower demand from India as it did not lower import duties as expected.

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

Palm oil may break a resistance at 3,602 ringgit per tonne and rise into a range of 3,691 ringgit to 3,757 ringgit, Reuters technicals analyst Wang Tao said.

($1 = 4.1180 ringgit)

(Reporting by Bernadette Christina Munthe; Editing by Shailesh Kuber)