Yates is testifying for the first time since Attorney General William Barr moved to dismiss charges against Trump's first national security adviser Michael Flynn, who pleaded guilty to former special counsel Robert Mueller's team for lying to the FBI.
Yates, who is testifying remotely, did not weigh in on the controversies surrounding Flynn's prosecution in her opening statement, but defended the decision to scrutinize Flynn in the face of Russia's interference in the 2016 election and Flynn's intercepted phone calls with Russian Ambassador to the US Sergey Kislyak, in which they discussed US sanctions.
Yates played a key role in Flynn's firing as national security adviser in 2017, warning the White House about Flynn's calls with Kislyak, in which Flynn lied to senior members of the Trump administration -- and later the FBI -- that they discussed US sanctions.
Unions have accused shipbuilder Austal of exploiting Filipino workers just months after being awarded a lucrative contract with the Royal Australian Navy.
Austal rejected the union claims and said it was normal practice for the company to rotate employees through its shipyards in Australia and Asia for training purposes on a voluntary basis.
Austal is also a major shipbuilder for the US Navy at its operations in Mobile, Alabama, and a contender to buy strategically important shipyards in the Philippines as tensions escalate in the South China Sea. In May, the company was awarded a $324 million contract to build six Cape-class patrol boats for the Australian navy at its operations in Western Australia.
The Australian Manufacturing Workers Union questioned how Defence Minister Linda Reynolds could award the work to a company that appeared to be underpaying imported labour.