COMMODITIES-Oil firms on Russian gas dispute, copper up

* More supply cuts emerge from Russian gas row

* Copper rises to almost 5-week high

* Gold down 2 pct as dollar hits 3-week high versus euro

* Soy up on S. American weather, strong demand, firm oil

(Recasts, adds comments, updates prices pvs SINGAPORE)

By Peter Blackburn

LONDON, Jan 6 (Reuters) - Oil hit a one-month high above $50 a barrel on Tuesday as Israel's incursion into Gaza and a deepening dispute between Russia and Ukraine over natural gas prices sharply disrupted supplies to most of Europe.

Copper jumped more than 7 percent leading other industrial metals higher on buying before an annual re-rating by commodity indices. But gold slipped as the dollar firmed against the euro.

U.S. soybeans firmed on poor weather in major south American producing countries and sugar rose in sympathy with higher oil.