Sen. Lindsey Graham said Tuesday he won't approve a critical surveillance provision until politically damaging leaks of classified information are investigated and brought under control.

Graham said he isn't ready to approve legislation to reauthorize Section 702 of the Foreign Intelligence Surveillance Act, which allows the National Security Agency to monitor telephone communications and Internet data generated by foreign nationals but can also sweep up Americans.

Graham, a senior member of the Judiciary Committee, which will consider the legislation, said he first wants to determine who has been leaking FISA-gathered intelligence to the media. The leaks began as soon as President Trump took office and have been damaging to the Trump administration.

"As big a fan as I am of incidental collection, I'm not going to reauthorize a program that could be politically manipulated," Graham said Tuesday.

Graham added he also wants to investigate whether the Obama administration used the FISA law to hurt Trump.

Graham is among a growing group of Republicans who have in the past voted for FISA renewals but are angered by the leaks about the Trump administration.

House Intelligence Committee Chairman Devin Nunes, R-Calif., said the FISA leaks would make renewing the law difficult in the House.

The surveillance provision expires at the end of this year. It's considered to be a key counter-terrorism tool.

On Tuesday, Sen. Tom Cotton, R-Ark., and more than a dozen GOP lawmakers on the Intelligence Committee introduced a permanent reauthorization of Section 702 and other provisions of the FISA.