WASHINGTON (Reuters) — President Joe Biden’s nomination of Colin Kahl to be the Pentagon’s top policy adviser ran into a roadblock on Tuesday when two Democratic senators said they would not back him until the president committed to a more diverse Cabinet.

Senator Tammy Duckworth told reporters she would vote no until the Biden administration made such appointments or committed to naming an Asian-American Pacific Islander (AAPI) candidate to a Cabinet position.

“They can call me and tell me what the proposal is (for such nominations),” Duckworth, who is Thai American, said. “But until then, I am a no vote on the floor, on all non-diversity nominees.”

A second Democrat, Senator Mazie Hirono, also said she would not back Kahl in the full Senate without a commitment on diversity from Biden. She said, however, she would vote to advance Kahl’s nomination to the full Senate when the Armed Services Committee meets on Wednesday.

The U.S. AAPI community has reported a spike in hate crimes since March 2020, when then-President Donald Trump began referring to COVID-19 as the “China virus.”

Concern intensified this month after six Asian-American women were among eight people killed in a shooting in Atlanta.

Biden defended his administration’s approach to diversity.

“We have the most diverse Cabinet in history,” the president told reporters in Columbus, Ohio. “We have a lot of Asian Americans that are in the Cabinet and in sub-Cabinet levels.”

Kahl, who served as national security adviser to Biden when he was vice president in the Obama administration, is a prime target of Republicans aiming to torpedo several Biden picks over their social media activity.

Critics accused Kahl of making comments on Twitter that were too partisan.

Neera Tanden withdrew from consideration this month as Biden’s nominee for Office of Management and Budget director after criticism over previous social media posts. She would have been the first Indian-American woman in the position.

Democrats have repudiated such concerns from Republicans, noting party members’ loyalty to Trump, who used his Twitter feed to insult political opponents.

But with the Senate evenly divided and Vice President Kamala Harris able to break a tie, any nominee would need the support of every Democrat to be confirmed.

Reporting by Patricia Zengerle; Additional reporting by Nandita Bose in Columbus, Ohio; Editing by Lisa Shumaker and Peter Cooney