WASHINGTON (Reuters) - A review of the U.S.-China trade deal initially slated for Saturday will be delayed due to scheduling issues and no new date has been agreed, according to sources familiar with the plans.

U.S. Trade Representative Robert Lighthizer, U.S. Treasury Secretary Steven Mnuchin and Chinese Vice Premier Liu He had been expected to meet via videoconference on Aug. 15, the six-month anniversary of agreement's taking effect.

One source familiar with the talks said the delay stemmed from continued meetings of senior Communist Party leaders at the seaside town of Beidaihe on China's northeast coast.

Specific dates for the secretive party conference, normally held in August, are never published.

The delay did not reflect any substantive problem with the trade deal, the source said, adding: "The new date has not been finalized yet."

The U.S. Trade Representative's office did not respond to a Reuters query about plans for the review.

China is well behind the pace of purchases of U.S. exports needed to meet first-year targets for major increases in its purchase commitments. It was slated to buy $77 billion more than in 2017 this year, and $123 billion over the 2017 level in 2021.

Trump administration officials have signaled that they are satisfied with the pace of purchases in recent weeks and have no plans to abandon the trade deal, which also includes some increased access for U.S. financial services firms in China, strengthened intellectual property protections and removal of some agricultural trade barriers..

The trade deal has emerged as a lone source of stability amid significant strain in the U.S.-China relationship over the coronavirus pandemic, human rights crack-downs and U.S. sanctions on Chinese companies and phone apps.