WASHINGTON — The Department of Veterans Affairs is improperly spending at least $5 billion a year for medical care and supplies being purchased in violation of required practices for competitive bidding and written contracts, a senior VA official said Thursday.

“Gross mismanagement” by senior agency leaders has wasted billions of dollars and made a “mockery” of federal laws regarding purchasing of goods and services, said Jan Frye, deputy assistant secretary for acquisition and logistics.

Illegal purchases have been made for pharmaceutical drugs and medical supplies, putting veterans at risk and exposing the agency to widespread “fraud, waste and abuse,” Frye said.

“I can state without reservation that VA has and continues to waste millions of dollars by paying excessive prices for goods and services due to breaches of federal laws,” Frye told the House Veterans Affairs subcommittee on oversight and investigations.

VA Secretary Robert McDonald said in a statement he appreciates the issues Frye brought to light. Frye first raised concerns in a 35-page memo to McDonald earlier this year.

As Frye made clear in his March memo and in testimony Thursday, “there are many acquisition paths within the Veterans Health Administration” to provide health care for veterans, McDonald said. “It is important to note that the vast majority of the funding identified in the memo went to provide veterans needed care in the community” and was not wasted, McDonald said.

McDonald said he has directed the VA’s inspector general to review Frye’s allegations. Any findings of wrongdoing or evidence of harm to veterans will be shared with the Justice Department for possible criminal prosecution, McDonald said.

Rep. Mike Coffman, R-Colo., chairman of the oversight panel, said “weak internal controls” at the VA have resulted in “serious violations of procurement laws,” mostly through a purchase-card program intended as a convenience for minor purchases of up to $3,000. Instead, VA employees have used the cards to buy billions of dollars’ worth of medical supplies and drugs without contracts.

In all, VA has understated its annual acquisition totals by at least $5 billion in each of the past five years, “due to our inexcusable failure to acquire a substantial quantity of goods and services in accordance with federal laws and regulations,” Frye said.