United Parcel Service

(UPS) - Get Report

reported quarterly earnings in line with estimates Friday morning, saying international business growth offset volume declines in the U.S.

The delivery services company, which released its second-quarter results early due to its recent inclusion in the

S&P 500

, said it earned $611 million, or 54 cents a share, in line with the company's

previous guidance, but down from $630 million, or 55 cents a share, in the year-ago quarter. Analysts polled by Thomson Financial/First Call had been looking for 54 cents.

Revenue was up about 2.5% to $7.68 billion from $7.49 billion last year.

UPS said its domestic package business saw a decline in package volume that accelerated towards the end of the quarter, due in part to its ongoing contract negotiations with the Teamsters union. Total U.S. revenue dropped 1.2% in the quarter to $5.91 billion. Previously, the company had said that business was being diverted to rivals because of the impasse.

International business picked up in the quarter, however, with operating profit more than doubling to $62 million on a 9% revenue increase.

"Clearly the contract talks and the continuing weakness in the U.S. economy reduced earnings in the domestic business, but we're pleased with the momentum outside the United States," the company said in a statement.

Additionally, UPS said disclosing its results early would facilitate its planned 32.5 million share offering to occur simultaneously with its inclusion on the S&P index.

Looking ahead, UPS said its ongoing labor negotiations made it impossible to offer any guidance at this time.

Shares of UPS fell about 1.6% to $61.50 on the news in early premarket trading after closing at $62.50 Thursday.