(Updates to U.S. market open, adds quote, data, changes dateline, previous LONDON)
* Dollar set for worst start to year since 2006
* Stocks cement biggest losses since mid-December
* Hopes of Trump fiscal boost tempered by travel ban
* Euro jumps on "undervalued" comment from Trump adviser
By Dion Rabouin
NEW YORK, Jan 31 (Reuters) - The dollar headed for its worst start to a year in over a decade on Tuesday, while stocks cemented their biggest losses in six weeks as U.S. President Donald Trump added uncertainty to the market following stringent curbs on travel to the United States.
Comments from Trump's top trade adviser, Peter Navarro, that Germany was using a "grossly undervalued" euro to gain advantage over the U.S. knocked the dollar in early North American trading. followed up on those comments in a meeting with the chief executives of several top drugmakers, during which he said drug companies had outsourced production because of currency devaluation by other countries. dragged the dollar even lower. It fell nearly 1.5 percent against the yen JPY= , and the dollar index .DXY , which tracks the greenback against six rival currencies, dropped to its lowest since Dec. 8. hopes for a fiscal boost to the world's largest economy under Trump have been tempered by controversial and protectionist policies that have seen him suspend travel to the United States from seven Muslim-majority countries.
Trump also announced he was firing acting Attorney General Sally Yates for her refusal to defend his travel restrictions on Muslim nations and refugees. She was promptly relieved of her duties for what was termed a "betrayal" by the White House.
Wall Street, already lower on weak earnings reports from a slate of companies, sunk further after Trump's meeting in which he called on the pharmaceutical industry to boost their U.S. production and lower their prices.
"You've got a very busy week for earnings, economic data and central bank meetings," said Adam Sarhan, chief executive officer at 50 Park Investments in Florida.
"So when you add all this political uncertainty, that leads investors to sell stocks first and ask questions later, especially after a historic run."
The Dow Jones Industrial Average .DJI fell 154.9 points, or 0.78 percent, to 19,816.23, the S&P 500 .SPX lost 11.27 points, or 0.49 percent, to 2,269.63 and the Nasdaq Composite .IXIC dropped 28.34 points, or 0.5 percent, to 5,585.38.
Nine of the 11 major S&P indexes were lower, with technology .SPLRCT and consumer discretionary .SPLRCD stocks weighing the broader index the most. S&P 500 healthcare sector .SPXHC , however, was last up 0.8 percent.
MSCI's gauge of the world's top 46 stock markets .MIWD00000PUS slipped 0.15 percent Tuesday, after suffering its largest loss in a month and a half on Monday.
European bourses .STOXX also fell, dropping 0.3 percent, after big losses on Monday.
MSCI's broadest index of Asia-Pacific shares outside Japan .MIAPJ0000PUS fell 0.6 percent while Japan's Nikkei .N225 dropped 1.7 percent, its biggest fall in almost three months.
Supported by signs of accelerating momentum in the global economy, most stock markets remained up on the month overall. MSCI's ex-Japan Asian shares index was up 6.1 percent this month while its index of world markets was up 2.6 percent.
Benchmark German government bond yields edged higher as the euro zone posted better-than-expected inflation and growth data. ECONALLEZ GVD/EUR
U.S. Treasury yields fell in the wake of Trump's comments and following U.S. consumer confidence and manufacturing data that missed expectations. dollar suffered broad losses, falling to its lowest against the yen since Nov. 30 and its lowest against the euro EUR= since Dec. 8.