Brett Giroir, White House official, claimed that the Trump administration has done "everything that they can do" to increase testing capacity, while the U.S. continues to see a hiking number of COVID-19 cases and disappointing testing delays as well as supplies shortage.

In the one-on-one interview with CNN TV program "The Lead", the official said the Trump administration has exhausted all the executive authority to help ensure that all Americans who want a COVID-19 test can get one.

"We want to increase testing. There is no physical way to do 5 million tests per day in this country. If there's a way to turn it from 1 million to 5 million today, let me know," Brett Giroir said.

"I'm going to say, definitively, the Trump administration had exhausted its executive authority to acquire additional supplies for labs processing COVID-19 tests," said Giroir, when asked if he thought everything had been done during the interview. 

However, the public health expert said the U.S. federal government needs to seize a larger leadership role in coordinating the whole testing and containment against infections and focused more on national effort to identify and solve current issues in the testing supply chain.

Some Americans can get access to testing kits, yet the wait time for test results is too long for them, and this can also hinder medical abilities to effectively track the spread of the virus. 

The fewer tests have led to the seven-day positivity rate climbing. The Texas Department of State Health Services did not respond Wednesday to questions about the decrease in testing numbers. The State of Texas surpassed 9,000 confirmed coronavirus deaths Wednesday, while testing again dropped to the lowest levels since June, and infection rates hit another record. The state on Wednesday reported over 300 additional deaths, bringing the total number of confirmed new COVID-19 deaths over the past week alone to more than 1,600.

Los Angeles Mayor Eric Garcetti said this week he has convened a team of public health experts, bioscience executives, government leaders, and philanthropists to push for accelerated research, development, and production of low-cost, do-it-yourself diagnostic kits, which are based on paper-strip designs that can be used frequently and produce results in minutes, similar to home pregnancy tests.

When paired with expanded contact-tracing to locate and quarantine other exposed individuals, it's important to get the testing done as quickly and effectively as possible in breaking the COVID-19 transmission cycle, according to Harvard University epidemiologists.

(With input from agencies)