WASHINGTON — So much for détente.

After a brief truce of sorts between the White House and business leaders, the top lobbyist at the U.S. Chamber of Commerce took aim at President Obama on Tuesday over an as-yet unannounced plan to force government contractors to disclose their political giving.

The lobbyist, R. Bruce Josten, said in an interview that the powerful business bloc “is not going to tolerate” what it saw as a “backdoor attempt” by the White House to silence private-sector opponents by disclosing their political spending.

“We will fight it through all available means,” Mr. Josten said. In a reference to the White House’s battle to depose Libya’s leader, Col. Muammar el-Qaddafi, he said, “To quote what they say every day on Libya, all options are on the table.”

While no final decision has been announced, the White House has acknowledged that Mr. Obama is considering issuing an executive order requiring all would-be federal contractors to disclose direct and indirect political spending of more than $5,000.