File photo taken on July 13, 2017 shows US Health and Human Services (HHS) Secretary Tom Price (R) speaking at a news conference at the US Department of Justice in Washington DC, the United States. US Health and Human Services (HHS) Secretary Tom Price resigned on Sept 29, said the White House. [Photo/Xinhua]

WASHINGTON - US Health and Human Services (HHS) Secretary Tom Price resigned on Friday amid increasing fire over his frequent and expensive private jet trips, becoming the first cabinet secretary to leave the Donald Trump administration.

Price offered his resignation on Friday and President Donald Trump accepted it, White House Press Secretary said in a statement.

"The President intends to designate Don J. Wright of Virginia to serve as Acting Secretary, effective at 11:59 pm on Sept 29, 2017," the statement said. Wright currently serves as the Deputy Assistant Secretary for Health and Director of the Office of Disease Prevention and Health Promotion.

Price has been under heavy fire since US media outlets found he had flown on at least 26 private flights since May, including five domestic flights within one week this month.

He apologized on Thursday, saying he will pay a portion of the costs of his official travelling on private charter planes and will permanently halt his use of charter flights for official business as the health secretary.

However, the total cost of the private jets Price flew on was reportedly more than $400,000 and Price would pay only $51,887.31 for his seat on those planes, according to an HHS spokesperson.

Price is not covering the cost for his staffers who flew with him on those charter planes, said the spokesperson on Thursday.

Many of Price's flights were between major cities that offered inexpensive alternatives on commercial airlines. One leg was from Washington DC to Philadelphia, a distance of some 130 miles (208 kilometers).

Moreover, on some of those trips, Price reportedly mixed official business with personal affairs such as having a lunch with his son.

On Wednesday, Trump said he was not happy with Price's private jet travel, saying "we'll see" when asked whether he will remove Price over the issue.

The House Oversight Committee on Wednesday launched a bipartisan investigation into the use of private planes by all members of the Trump cabinet. Senator Chuck Grassley on Thursday sent a letter asking the White House to detail its efforts to control officials' travel costs.

Price has frequently criticized government waste since his appointment as health secretary and during his tenure in the House of Representatives, where he once chaired the House Budget Committee.