Updated

A House panel and the State Department say they are working to determine a date for Secretary of State John Kerry to testify about Benghazi after he was subpoenaed to testify May 21 about the administration's response in providing emails and other documents to the panel investigating the Sept. 11, 2012 attack.

State Department spokeswoman Jen Psaki said in a statement Kerry will be in Mexico on the day he was subpoenaed to testify, so they are working with the House Oversight and Government Reform Committee to establish a different date.

Rep. Darrell Issa, chairman of the House Oversight and Government Reform Committee,  subpoenaed Kerry earlier this month.

"The State Department has told the Committee that they are committed to finding an alternative date in the near future for Secretary Kerry to testify before the Oversight Committee," Frederick Hill, a spokesman for the panel, said Monday. "As such, Chairman Issa agreed to lift the subpoena obligation for May 21."

The department and committee are looking at a new date for the secretary's testimony in late May or early June.

Psaki said the department and the committee "have been in touch to determine how to resolve their subpoena, but we have not yet made arrangements for a hearing date."

She said that "given the pressing foreign affairs issues that the Secretary is actively engaged on and the committee's focus on document production issues, we would like to explore whether there are better means of addressing the committee's interests, including finding a more appropriate witness."

The Oversight Committee is pressing ahead with its investigation even as the House established a new select committee to conduct an inquiry into the assault that killed four Americans, including U.S. Ambassador Chris Stevens.

Republicans insist that the Obama administration has misled the American people about the attack, downplaying the terrorist assault weeks before the presidential election. Democrats point to multiple investigations, bipartisan as well as independent, and maintain that an eighth inquiry is unnecessary.

In the Senate on Monday, Democrats blocked a Republican push for a joint House-Senate investigation.

Sen. Ted Cruz, R-Texas, sought support for the Senate to participate in the inquiry. Cruz argued that questions still remain, including whether Obama slept the night of the attack.

Democratic Sen. Bob Menendez of New Jersey objected, saying the probe is politically motivated and without merit.

Speaker John Boehner appointed seven Republicans to the special panel last week. Democrats are weighing whether to participate and appoint their five members.

The Associated Press contributed to this report