WASHINGTON (NEXSTAR) - The U.S. is investigating how classified documents ended up on the social media app "Telegram" Friday. They show Israel's potential plans to attack Iran in retaliation for its missile attack Oct.1.  "Certainly, we are concerned," White House Press Secretary Karine Jean-Pierre said.  The White House says the Justice and Defense Departments are investigating the leak.  "They're being looked into. It's being investigated by the appropriate authorities," Jean-Pierre said.  West Virginia Republican Sen. Shelley Moore Capito told NewsNation the U.S. needs to find out who did this.  "To think that there's this huge breach of trust, which appears to be, is just unconscionable on our part," Moore Capito said.  Moore Capito says Israel's plans could be compromised by what's in those documents, including: "certain movements of aerial assets by Israel, certain dates... I think could then be used by Iran to either defend themselves or to counterattack." White House National Security Communications Advisor John Kirby said he doesn't expect more documents to come out.  Meanwhile, Secretary of State Antony Blinken is heading to Israel to press for more humanitarian aid and a ceasefire, something thought to be within reach after Israel killed Hamas's leader last week.  "We feel strongly that there is an opportunity to move the ball forward," State Department Spokesman Vedant Patel said.  Blinken's visit comes as Israel steps up strikes on Lebanon, targeting what it says is the financial infrastructure of the terrorist group Hezbollah. The attacks have displaced thousands of civilians.  "We of course support efforts to degrade them, degrade their infrastructure. We want to make sure though that civilians are protected," Patel said.  This is Blinken's 11th visit to the Middle East since the war in Gaza began last year.