By 9:33 a.m., the FTSE 100 was down 7.39 points at 4,226.96, after closing on Monday at its lowest since April 29. The index has fallen 3.9 percent so far in June, reversing three months of consecutive monthly gains since the all-time low reached in March.

Howard Wheeldon, strategist at BCG Partners in London, said the FTSE 100 is taking a breather, in tandem with equity moves around the globe.

"What we will see as this week moves on are more sideways moves. Sideways momentum and stagnation are showing themselves right now," he said.

U.S. stocks suffering their worst one-day loss in two months on Monday, while Asian stocks tumbled as investors took profits.

Oil and gas firms fell as oil stayed below $68 a barrel. Royal Dutch Shell , BP and BG Group lost between 0.3 and 1.1 percent.

Drugmakers, perceived as safe-bet assets, rose with Shire , AstraZeneca and GlaxoSmithKline adding between 0.6 and 1.6 percent. Shire rose 1.5 percent.

Anglo American shed 0.7 percent after rejecting a proposed merger with Xstrata , which gained 1.3 percent.

Anglo American pared losses as traders cite market talk of a bid from Chinalco. Both Chinalco representatives in London and officials from Anglo American declined to comment.

Other miners Eurasian Natural Resources , Rio Tinto , Kazakhmys added between 0.2 and 1.1 percent.

Supermarkets Sainsbury and Tesco gained 0.9 percent and 0.7 percent respectively.

Banks took the most points off the index, with Barclays, Lloyds Banking Group and Standard Chartered falling between 0.8 and 1.8 percent.

U.S. HOUSING

The National Association of Realtors (NAR) releases existing home sales for May at 1400 GMT, with economists polled by Reuters expecting a 4.81 million annualised unit total against 4.68 million annualised units in April.

Investors are likely to be watching out for comments on the progress of quantitative easing and signs of recovery in the market following the Federal Reserve Open Market Committee meeting which begins on Tuesday.

Among other FTSE 100 gainers, Thomson Reuters rose 5.5 percent, after the global information firm said it plans to delist from the London Stock Exchange, severing a key connection with Reuters' British roots.

Aggreko fell 3.6 percent after the temporary power provider said it expects first-half profit to rise as its international power division continues to grow, but said trade at its local business had slowed in the second quarter.

(Editing by Mike Nesbit)