The White House has withdrawn the nomination of Elaine McCusker to become Pentagon comptroller.
The Pentagon announced Wednesday that top policy official John Rood has resigned.
Under the Defense Department's budget plan, funds for the European Defense Initiative would be cut to $4.5 billion.
Fighting between Russia-backed rebels and Ukrainian troops has killed more than 14,000 people since 2014.
The White House has been scrutinizing Bolton's book for classified materials.
Ukraine's President Volodymyr Zelenskiy acknowledged the recording's authenticity.
For days after the Jan. 8 shootdown, Iran denied that it fired missiles at the plane.
Hassan Rezaeifar was quoted by the state-run IRNA news agency as saying "we have no plans to send them out.”
Iran does not have the equipment necessary to be able to analyze the damaged black boxes quickly.
The aid in question was held up last summer on orders from Trump but was released in September.