Sen. Lindsey Graham Lindsey Olin GrahamSteele Dossier sub-source was subject of FBI counterintelligence probe Hillicon Valley: Subpoenas for Facebook, Google and Twitter on the cards | Wray rebuffs mail-in voting conspiracies | Reps. raise mass surveillance concerns Key Democrat opposes GOP Section 230 subpoena for Facebook, Twitter, Google MORE (R-S.C.) dialed up his rhetoric on Iran after a U.S. drone was shot down by the country, warning that a military response is "where we're headed if nothing changes."

Graham made the comments to reporters on Thursday ahead of a briefing on the downed drone, adding that Iran needs to "knock this shit off."

U.S. Central Command (Centcom) said Thursday that an Iranian surface-to-air missile system shot down the drone in international airspace over the Strait of Hormuz in an "unprovoked attack." It also denied Iranian claims that the drone was over Hormozgan Province in southern Iran.

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Graham also said that he told President Trump Donald John TrumpSteele Dossier sub-source was subject of FBI counterintelligence probe Pelosi slams Trump executive order on pre-existing conditions: It 'isn't worth the paper it's signed on' Trump 'no longer angry' at Romney because of Supreme Court stance MORE to tell Iran "all bets are off" if uranium enrichment continues.

"You need to tell the Iranians that if they increase their enrichment program for uranium that would be a provocative act towards United States and Israel and all bets are off," Graham said.

GOP Sen. Lindsey Graham says he spoke with President Trump this morning on Iran: “‘You need to tell the Iranians that if they increase their enrichment program for uranium that would be a provocative act towards United States and Israel and all bets are off’” pic.twitter.com/q89TdiZlA9 — CNN Politics (@CNNPolitics) June 20, 2019

The South Carolina lawmaker also released a statement warning Iran about enrichment.

“It is imperative the United States clearly inform the Iranians that any effort to increase uranium enrichment will be seen as a hostile act against the United States and our allies in Israel, and will not go unanswered," Graham said.

“When it comes to a military response – if necessary – it should be focused on Iranian naval capabilities and the oil refineries which are the economic lifeblood of this murderous regime.”

Graham's comments come amid rising tensions between the U.S. and Iran.

Washington accused Tehran of bombing two oil tankers in the Gulf of Oman last week, which Iran denied.

The Pentagon also announced this week that it would deploy an additional 1,000 troops to the Middle East to address “air, naval, and ground-based threats” in the region.

Tehran responded by announcing it would surpass the limit for its uranium enrichment that was agreed to in the Obama-era nuclear deal. Trump withdrew the U.S. from the deal last year, but Iran has continued to keep within the agreement’s bounds until now.

Rebecca Kheel contributed