As President Barack Obama and congressional leaders were in a final effort to reach a budget agreement before year's end, Starbucks this week began urging workers in its roughly 120 Washington, D.C.-area shops to write the words "come together" on customers' cups.

A spokesman for the world's largest coffee chain said the company would expand the effort to all U.S. stores, continuing through next week.

"Stores from across the country have been asking if they could join in and we have been saying absolutely yes," Starbucks spokesman Jim Olson said in an email late Friday.

"Based on this unprecedented response, we are inviting all of our partners at U.S. stores to start signing their customers' cups with Come Together through next Friday," Olson said.

Starbucks' cup campaign aims to send a message to sharply divided politicians and serve as a rallying cry for the public in the days leading up to the January 1 deadline to avert harsh across-the-board government spending reductions and tax increases that could send the U.S. economy back into recession.

"We believe the (Washington) DC effort caught on so swiftly because they Come Together message is such a simple and respectful gesture that expresses the optimism that is core to our country's heritage and to Starbucks mission," Olson said.

"This is an important moment for Starbucks to use its scale for good and give Come Together an even louder voice - as we move from signing tens of thousands of cups in DC to tens of millions of cups across the U.S. over the course of next week."

(Reporting by Julie Ingwersen; Editing by Vicki Allen)

• A Permanent Economic Emergency