FILE PHOTO: A corn field and storage bins are seen on the Doug Zink farm near Carrington, North Dakota, U.S., August 8, 2019. REUTERS/Dan Koeck

CHICAGO (Reuters) - The U.S. Department of Agriculture (USDA) has so far paid farmers $14.03 billion of a promised $28 billion as compensation for the effects of Washington’s trade disputes with China, an agency official told Reuters on Wednesday.

The agency has paid $5.43 billion from its latest round of trade aid - up from $4.07 billion in mid-September - as of Monday, USDA Communications Director Michawn Rich said in an email. The agency also has paid out $8.6 billion in the first round of its Market Facilitation Program to date, she said.

U.S. farmers helped carry Republican President Donald Trump to his surprise election victory in 2016. But they are among the hardest hit from his trade policies that led to tariffs with key trading partners such as China, Canada and Mexico.

The Trump administration in July announced $16 billion to compensate farmers for lost sales due to China’s retaliatory tariffs on U.S. agricultural products, on top of $12 billion pledged in last year’s aid package.

The aid program has faced challenges from farmers complaining of difficulty in signing up, confusion over payment rates and application processing that was delayed due to last year’s partial federal government shutdown.

USDA has received 418,056 applications for the 2019 aid program since enrollment opened on July 29 - up from 302,397 applications it had received as of Sept. 16, Rich said.

USDA also said it had received 1.03 million applications for the initial aid round.