Dec 19 (Reuters) - Amazon.com ( AMZN ) workers at seven U.S.

facilities walked off the job early on Thursday during the

holiday shopping rush, aiming to pressure the retailer into

contract talks with their union.

Warehouse workers in cities including New York, Atlanta and

San Francisco are taking part in the "largest" strike against

Amazon ( AMZN ), said the International Brotherhood of Teamsters, which

represents about 10,000 workers at 10 of the firm's facilities.

The company, however, said it does not expect any effect on

its operations during one of the busiest times of the year.

Unions represent only about 1% of the workforce of Amazon ( AMZN ),

one of the largest companies in the U.S. by market value, and it

has multiple locations in many metro areas.

The union had given Amazon ( AMZN ) a Dec. 15 deadline to begin

negotiations and warehouse workers had recently voted to

authorize a strike.

"If your package is delayed during the holidays, you can

blame Amazon's ( AMZN ) insatiable greed," Teamsters' General President

Sean O'Brien said late on Wednesday.

"We gave Amazon ( AMZN ) a clear deadline to come to the table and do

right by our members. They ignored it. This strike is on them."

The retailer's shares were trading nearly 1% higher

in premarket hours, a sign that investors do not expect a big

disruption from the strike.

The Teamsters have "intentionally misled the public" and

"threatened, intimidated and attempted to coerce" employees and

third-party drivers to join them, an Amazon ( AMZN ) spokesperson said on

Thursday.

Observers said Amazon ( AMZN ) was unlikely to come to the table to

bargain as that could open the door to more union actions. It

employs more than 1.5 million people globally and has said it

prefers direct relationships with workers.

Still, the company has responded to recent organization

efforts with legal challenges. Amazon ( AMZN ) has filed objections with

the National Labor Relations Board (NLRB) over a 2022 union vote

in Staten Island, alleging bias among agency officials.

It also challenged the constitutionality of the NLRB in a

September federal lawsuit.

Earlier this year, the company announced a $2.1 billion

investment to raise pay for fulfillment and transportation

employees in the U.S., increasing base wages for employees by at

least $1.50 to around $22 per hour, a roughly 7% increase.