* World shares gain as China signals support for growth
* U.S. stocks flat to lower; Apple results awaited
* Copper, oil prices rise on optimism over China
NEW YORK, July 23 (Reuters) - World stock markets rose to near five-year highs on Tuesday, boosted by news that China was moving to support its cooling economy, while the dollar fell to one-month lows.
Major U.S. equity indexes were flat to slightly lower after a mixed batch of earnings, including chemical maker DuPont and insurer Travelers.
The Standard & Poor's 500 index, which on Monday posted a record closing high for a third straight session, came within 2 points of its milestone of 1,700 before turning lower.
Copper and oil prices rebounded from early losses after China's president, Xi Jinping, in remarks published on Tuesday, emphasized the government's determination to restructure the country's slowing economy. Yields on low-risk U.S. and German government debt rose as higher equity prices reduced their safe-haven appeal.
Oil prices also rose on optimism on China, as did shares of mining companies. Local media in China reported the government was looking to increase investment in railway projects to help digest a capacity glut in steel, cement and other construction projects.
"Managing to keep (Chinese growth) above 7 percent will certainly be viewed as a positive stance," said IG Markets analyst Alastair McCaig in London. "But they really have only five months to prove their words are worth their weight."
The MSCI world equity index, which tracks stocks in 45 countries, climbed 0.14 percent to 376.08, within about 6 points of the five-year high set in May.
In midday trading, the Dow Jones industrial average was up 15.66 points, or 0.10 percent, at 15,561.21. The Standard & Poor's 500 Index was down 2.27 points, or 0.13 percent, at 1,693.26. The Nasdaq Composite Index was down 12.64 points, or 0.35 percent, at 3,587.74.
Wall Street has moved higher in 11 of the past 12 sessions. The S&P 500 is up about 20 percent for the year.
But U.S. shares will likely struggle to extend their winning streak unless there are more upbeat earnings and economic developments, analysts said.
"Valuations are decent, there's positive monetary pressure, earnings are just OK... it's hard to get people excited but the market keeps grinding higher," said John Manley, chief equity strategist at Wells Fargo Funds Management in New York.
"It will be slow over the summer, but the market will have an upward bias."
Apple Inc is due to report after the closing bell. The tech giant is expected to post a smaller quarterly profit and its financial report may come under intense scrutiny. The stock was down 0.8 percent at $422.73.
European top shares closed lower on a late wave of selling, with semiconductors group STMicroelectronics leading the way down after weak results. The broad FTSE Eurofirst 300 index closed down 0.2 percent at 1,208.41 points. StMicro tumbled 10.3 percent.
But mining shares rose on the news out of China, with Anglo American rising 2.1 percent and BHP Billiton gaining 2.0 percent.
In Asia, an upgraded economic outlook from Japan's government lifted Tokyo's Nikkei stock index 0.82 percent to 14,778.51.
DOLLAR SLIPS AGAIN
The dollar was stuck at a one-month low against a basket of currencies as an earlier bounce faded
Investors earlier bet that the currency recently had declined too far, too fast despite the debate about when the Federal Reserve would begin to slow its stimulus measures.
Fed Chairman Ben Bernanke's dovish remarks have emphasized that the U.S. central bank's bond buying will continue in some form and interest rates will likely remain low for the foreseeable future.
Heightened expectations that Japan's government will stick to expansionary policies after weekend elections weakened the dollar against the yen on Monday. The victory in parliament's upper house election on Sunday cemented Prime Minister Shinzo Abe's hold on power and gave him a stronger mandate for his programs to stimulate the world's third-biggest economy.
An earlier rise in U.S. 10-year Treasury note yields above the 2.50 percent level ahead of this week's $99 billion in coupon-bearing supply briefly propped up the dollar. The benchmark 10-year U.S. Treasury note was down 3/32 in price with a yield of 2.499 percent, up 1.5 basis points on the day.
German 10-year Bund yield, meanwhile, was 1.552 percent, little changed from Monday's close.
The dollar index fell 0.13 percent to 82.111. The greenback was up 0.1 percent against the yen at 99.75 yen after briefly trading back above the 100 yen level, while it was up 0.2 percent versus the euro at $1.3210.
In the commodities market, copper gained 0.1 percent at $7,038.50 a tonne in London, erasing early losses linked to worries about a supply glut and sluggish global demand.
Oil prices rebounded from early lows on optimism about China's efforts to avert a hard-landing of its economy. Brent oil rose 40 cents, or 0.37 percent, to $108.55 a barrel, while U.S. crude futures were up 7 cents, or 0.07 percent, at $107.01 a barrel.
Gold prices fell 0.09 percent to $1,333.84 an ounce as the dollar's bounce prompted buyers to pause after the metal posted its biggest one-day price rise in more than a year on Monday. Gold has recovered nearly $160 from a three-year low of $1,180.71 on June 28.