White House press secretary Jen Psaki on Wednesday criticized the Senate for not moving more quickly to confirm President Biden’s ambassadorial nominees, as only one of Biden’s political ambassadors has been confirmed more than six months after the inauguration.

“We are frustrated over the slow pace of confirmations, particularly for noncontroversial nominees,” Psaki told reporters at her Wednesday afternoon news briefing. “A number of these nominees who are sitting and waiting are highly qualified. A number of them have a lot of Republican support. So what is the holdup?”

Hours earlier, the Senate confirmed Ken Salazar, the former interior secretary and senator from Colorado, as U.S. ambassador to Mexico. Salazar is the first of Biden’s political ambassadors to be confirmed by the Senate.

Historically, some ambassadors are career Foreign Service officers while others are political ambassadors — individuals who are often allies of the president or major campaign donors.

So far, Psaki said, Biden has tapped nearly 275 nominees — including many outside the State Department — who have yet to be confirmed by the Senate. Biden has sent over more nominees than former president Donald Trump had by this point in his term and about the same number as former presidents Barack Obama and George W. Bush had, Psaki said.

“It’s important for us around the world to have qualified ambassadors who are confirmed by the Senate to lead our country and represent our country at this point in time,” she told reporters. “There are also a number of other positions — at the Treasury Department, at other domestic agencies — that could play a pivotal role as our country is continuing to deal with an economic recovery.”

The White House’s own slow decisions on its ambassadors, Republican maneuvering, and the Senate’s focus in recent weeks on pushing through a bipartisan infrastructure deal have all contributed to the backlog.

As the Senate wrapped up its work on the budget process early Wednesday morning, Senate Foreign Relations Committee Chairman Robert Menendez (D-N.J.) stood on the Senate floor and asked for unanimous consent for the approval of nearly 30 State Department and USAID nominees.

He was blocked by Sen. Ted Cruz (R-Tex.), who has repeatedly held up confirmations of Biden nominees in opposition to a controversial natural gas pipeline between Russia and Germany.

“We should be ashamed of holding the record for the longest delay in fully equipping the State Department and USAID to pursue the foreign policy, development and national security interests of the United States,” Menendez said. “Some members of this body call on the one hand for assertive American leadership on the global stage and at the same time they hold up these critical positions.”

The White House has been slow to announce some of the political ambassador slots in part because of diversity concerns, people familiar with the process told The Washington Post in June. Many of Biden’s longtime friends, allies and donors are White men, and the administration has been working to ensure the political ambassadors reflect gender and racial diversity.

“I will note that diversity has been a front-and-center priority for the president, for this administration and for our personnel department as they look to fill key posts, not just ambassador roles, but roles to serve in high-level positions in agencies,” Psaki said Wednesday.

Psaki also defended Biden’s nominations of political donors and other allies, noting that the work of those individuals in the private sector “does not mean that they’re unqualified.”

She declined to offer a percentage for Biden’s target number of political appointees.

During the 2020 Democratic presidential primary, Biden said he would not rule out appointing political donors to highly coveted ambassadorships, despite pressure from liberal Democrats, including Sen. Elizabeth Warren (Mass.).

“I’m going to appoint the best people possible,” Biden told reporters in December 2019. “Nobody, in fact, will be appointed by me based on anything they contributed.” But he added that some highly qualified people “may or may not have contributed.”

Biden and his aides have argued that naming both career diplomats and political appointees provides the administration with a range of experience.

The majority of the nearly 190 ambassadorial postings are filled by career State Department employees, and Biden has also committed to a lower percentage of political ambassadors than previous administrations.

In addition to Salazar, other members of Biden’s first slate of political ambassadors announced in June include Thomas R. Nides, a former State Department official, for U.S. ambassador to Israel; Julie Smith, a former Biden national security adviser, for ambassador to the North Atlantic Treaty Organization; and C.B. “Sully” Sullenberger III, who safely landed a plane on the Hudson River after a dual engine failure in 2009, as the ambassador to the Council of the International Civil Aviation Organization.

Anne Gearan and Tyler Pager contributed to this report.