WASHINGTON - US Senate Republicans blocked a popular piece of President Barack Obama's stimulus plan - one to raise taxes on millionaires to create or protect 400,000 jobs for teachers and firefighters.

The vote was 50-50 on Thursday evening, 10 short of the 60 votes needed to clear a Republican procedural roadblock.

The action came shortly before Democrats were expected to block a Republican bid to stimulate the economy by repealing a pending 3 percent business withholding tax.

The opposing positions underscored the difficulty of finding common ground on job creation, which is certain to be a key issue in the presidential and congressional elections in November 2012.