Toronto stocks set to open weaker after sharp fall

*TSX looks set for weaker open after Wednesday's fall

*Economic concerns in view as data digested

*Oil hits new high above $145 a barrel

TORONTO, July 3 (Reuters) - The Toronto Stock Exchange's main index looked set to open weaker on Thursday, extending the previous session's steep fall, as global markets stumbled and worries about the outlook for the economy remained in view.

In its largest decline since March, the Toronto benchmark index shed 3 percent in Wednesday's session, knocked sharply lower in a broad selloff amid heightened economic negativity, as well as weak coal companies.

Global economic concerns could remain in focus after the European Central Bank raised its key interest rate by a quarter point, as expected, marking its first increase in more than a year due to rising inflation.

Meanwhile, data showed U.S. employers cut workers from the payrolls for the sixth straight month in June, while the unemployment rate held steady at 5.5 percent.

The resource sector could see weakness, continuing Wednesday's losses as investors locked in profit, while worries about how long commodity prices can sustain their soaring heights also began to creep in.

"The ones that were a big percentage of the down move yesterday, like Potash Corp (POT.TO: Quote, Profile, Research) and Agrium (AGU.TO: Quote, Profile, Research), look like they're going to be lower again today," said Bruce Latimer, a trader at Dundee Securities.