Fighting is ongoing in northern Israel near the Lebanon border, where huge plumes of smoke are visible.

The Israel Defense Forces said there was an explosion Friday at the security fence adjacent to Hanita, Israel, which is along the border. The IDF said it's responding with artillery fire toward Lebanon.

"Additionally, an alert was activated concerning the infiltration of terrorists into the community," the IDF said, and Israeli "soldiers are currently searching the area."

The Israel Defense Forces said Hamas is using roofs of residential buildings in Gaza to launch its hostile unmanned aerial vehicles.

Israeli planes have targeted dozens of these launch sites, the IDF said.

"This is further proof Hamas deliberately uses civilian building for military purposes," the IDF said. "The IDF will continue to operate in order to destroy Hamas' hostile UAV capabilities."

In his first on-camera comments about Israel’s evacuation request for northern Gaza, Israeli Defense Minister Yoav Gallant urged Gaza residents to head south. He noted that Hamas will use them as "camouflage," “therefore we need to separate them."

"Those who want to save their life, please go south. We are going to destroy Hamas infrastructures, Hamas headquarters, Hamas military," he said.

Defense Secretary Lloyd Austin, who appeared at the press conference with Gallant, dodged ABC News' question about how Israel could end the Hamas terror threat without inevitably risking civilian lives. Austin called Israel's military "professional" and "disciplined."

Austin described how ISIS had also embedded themselves in civilian populations and how the anti-ISIS coalition "protected civilians and created corridors for humanitarian movement even in the midst of a pretty significant fight. So again, this is a professional force. It is well led, and I have every expectation that it will be disciplined."

Austin added, "I would tell you that in countering ISIS, I felt as if we were staring evil in the eye, it was truly evil. And what we've seen from Hamas, it takes that evil to another level."

-ABC News' Matt Seyler and Luis Martinez

During his meeting in Jordan with Palestinian Authority President Mahmoud Abbas, U.S Secretary of State Antony Blinken conveyed the need to cool tension across the West Bank and prevent the conflict from becoming broader, the State Department said.

“The Secretary extended his condolences to the families of Palestinian civilian victims of this conflict, and reiterated that Hamas does not stand for the Palestinian people's legitimate right to dignity, freedom, justice, and self-determination,” a readout from department spokesperson Matt Miller said.

"The Secretary thanked President Abbas and his team for their work to further calm the situation for the benefit of Palestinians, Israelis, and the tens of thousands of Americans who also call the West Bank home. Secretary Blinken reaffirmed the U.S. commitment to cooperation with the Palestinian leadership and people on efforts to ensure security for all," Miller continued.

The U.S. Embassy said it'll offer transportation for Americans looking to leaving Israel beginning on Friday.

"It will take some period of time to schedule everyone seeking to depart," the embassy said. "Transportation will be by air to Athens or Frankfurt, or sea from Haifa to Cyprus. You will not be able to choose your destination – we will assign you to the next available flight or ship."

"You should be prepared to depart within 8-12 hours of receiving notice of your booking. Each traveler may bring one small carry on item no more than 22 pounds (10 kg) and one suitcase no more than 35 pounds (16 kg)," the embassy said.

Delta Air Lines said it's partnering with the government to help set up flights through Athens.

United Airlines said it's adding extra flights with capped fares between Athens and Newark, New Jersey, and will use a larger plane for its Athens to Washington flight. "We’re in close touch with the U.S. State Department as it seeks to add additional options for Americans traveling from the region," United said.

American Airlines also said it is working "closely" with the State Department on its needs.

The U.S. expects "these initial travel options to facilitate the safe departure of thousands of U.S. citizens per week," State Department spokesperson Matthew Miller said in a statement.

A separate official said that the State Department remains in contact with "several thousand" American citizens in Israel, but it’s unclear how many will ultimately decide to leave. Some have already departed.

The State Department estimates that roughly 500,000 American citizens live in Israel.

-ABC News' Amanda Maile, Will Gretsky and Shannon Crawford