* FTSEurofirst 300 edges lower after Monday's 3-week high
* Financials among top losers, tech shares limit losses
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By Atul Prakash
LONDON, April 5 (Reuters) - European shares drifted lower on Tuesday as worries about the euro zone debt crisis hurt banks, though tech shares firmed after Texas Instruments offered $6.5 billion for National Semiconductor.
A downgrade of Portugal's credit rating by Moody's which said a new government would likely need financing support from the European Union as a matter of urgency dampened market sentiment. The European banking index fell 0.7 percent.
Portuguese bond yields rose to their highest since the euro's launch as the downgrade added to pressure on the government to seek a bailout.
The FTSEurofirst 300 index of top European shares was down 0.1 percent at 1,140.59 at 1142 GMT, after closing at a three-week high on Monday. The Thomson Reuters Peripheral Eurozone Countries Index fell 1.1 percent, while Portugal's PSI 20 was down 0.9 percent.
"The various fears have been offset in the last couple of weeks because companies are still doing well. But I see various pockets of weakness, in particular in the financial sector," said Richard Greenwood, fund manager at Bedlam Asset Management, which manages about $700 million.
Banks topped the losers' list, with Bank of Ireland down 5.9 percent, Millennium bcp falling 1.7 percent and Banco Santander off 2.5 percent.
Analysts said while the market had priced in a rate hike of 25 basis points by the European Central Bank on Thursday, there could be a knee-jerk reaction after the announcement. European equities, however, showed little reaction to China's hiking rates for the fourth time since October.
Losses were capped by firmer tech shares, with the sector index up 0.7 percent after Texas Instruments announced an agreed takeover bid for National Semiconductor at a 78 percent premium.
Infineon Technologies rose 2.5 percent, while STMicroelectronics added 2.6 percent.
TECHNICAL OUTLOOK
The Euro STOXX 50, the euro zone's blue-chip index, fell 0.6 percent to 2,938.14.
Analysts said while the short-term technical picture for the STOXX 50 index had improved following gains in the previous sessions, the index was looking relatively overbought.
"The latest price action shows that it could be encountering resistance in the form of its 50-day moving average. It is possible that selling pressures could develop at these levels," said Bill McNamara, technical analyst at Charles Stanley.
"Nevertheless, a close above 3,000 would strongly suggest the bulls are back in control, the implication being that we could yet see a run up to 3,040 before it loses momentum."
Greenwood of Bedlam said there was a flow towards the European gas sector, given low prices of gas against historical figures, energy efficiency and relative environmental benefits.
He said Bedlam recently included Royal Dutch Shell in its portfolio, adding there was a flow out of some banks due to concerns about the sovereign debt crisis.
Some caution prevailed ahead of the release of the Federal Open Market Committee's minutes from its March 15 meeting, due at 1800 GMT, for insight on the outlook for U.S. interest rates.
German group TUI AG rose 5 percent after saying it was in talks to sell a stake in container shipping business Hapag-Lloyd that it had wanted to float. (Additional reporting by Harpreet Bhal; Graphics by Scott Barber; Editing by Dan Lalor)