(Reuters) - Dollar Tree Inc DLTR.O forecast holiday-quarter profit below Wall Street estimates on Tuesday, as the discount retailer fell short in its efforts to counter the impact of the latest U.S. tariffs on Chinese imports, sending its shares down about 17%.

FILE PHOTO: A customer walks out of a Dollar Tree discount store in Austin, Texas, U.S., February 27, 2017. REUTERS/Mohammad Khursheed

The tariffs linked to the prolonged trade war between Washington and Beijing have been a pressure point for retailers, which source a large chunk of their merchandise from China.

Dollar Tree, which has been trying to cushion the tariff costs by negotiating price concessions with vendors and cancelling orders, said that if the tariffs are fully implemented it would increase its cost of goods sold by about $19 million in the current quarter.

Chief Financial Officer Kevin Wampler on a post-earnings call said that almost all of the tariff-related costs are due to levies imposed on Sept. 1, as their timing did not allow for significant mitigation by the company.

Shares of the company fell $19.00 to $93.25, wiping out $4.53 billion in market valuation.

The retailer expects a fourth-quarter profit in the range of $1.70 to $1.80 per share, well below the average analyst expectation of $2.02.

The company forecast holiday-quarter sales of $6.33 billion to $6.44 billion, the mid-point of which is below analysts’ estimate of $6.41 billion.

Dollar Tree said six fewer selling days between Thanksgiving, the traditional kickoff of the U.S. holiday shopping period, and Christmas this year would hurt its current-quarter sales.

The company also cut its full-year profit forecast, hurt by tariffs’ impact as well as costs related to store closures and renovations.

Earlier in August, Dollar Tree did not include costs linked to the proposed tariff hikes in its full-year forecast, saying that it was working to mitigate them.

The Chesapeake, Virginia-based company has been closing hundreds of Family Dollar stores this year while pouring money to renovate thousand more with new decor and addition of coolers, and alcoholic beverages to turn around the business.

It has also been adding snacks and frozen food segments at its namesake stores to attract consumers as it battles competition from big-box retailers Walmart Inc WMT.N and Target Corp TGT.N, as well as a shift to online shopping.

Dollar Tree’s same-store sales rose 2.50% in the third quarter ended Nov. 2, slightly below expectation of 2.54%.

Excluding items, it earned $1.08 per share, missing estimate of $1.13.