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.

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

negotiations and warehouse workers had recently voted to

authorize a strike.

Amazon ( AMZN ) said it does not expect any impact to its operations.

The union has "intentionally misled the public" and "threatened,

intimidated and attempted to coerce" employees and third-party

drivers to join them, a company spokesperson said.

Unionized facilities account for just 1% of Amazon's ( AMZN ) hourly

workforce and areas such as New York City have multiple

warehouses and smaller delivery depots, which could help Amazon ( AMZN )

blunt any potential strike impact.

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.

The retailer's shares were trading slightly higher

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

disruption from the strike.

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.