Originally Published: 15 DEC 23 00:00 ET

Updated: 15 DEC 23 07:41 ET

By Michael Williams and Kevin Liptak, CNN

Washington (CNN) — President Joe Biden’s national security adviser, Jake Sullivan, said Friday that there will be a transition to another phase of the war that is focused on “more precise ways” of targeting Hamas leadership.

“There will be a transition to another phase of this war, one that is focused in more precise ways on targeting the leadership and on intelligence driven operations that continues to deal with the ongoing threat that Hamas poses,” Sullivan said in a news conference in Tel Aviv.

Sullivan also said that the US wants to see results on Israel’s intent to avoid civilian casualties in Gaza.

“Israel selects targets and tries to distinguish between targets that hit Hamas, and those that that might take the lives of innocent civilians,” Sullivan said in response to a question from CNN’s Alex Marquardt.

“What we have consistently said is that Israel has the intent to make sure that it is drawing those distinctions clearly and in a sustainable way. And we want to see the results match up to that,” Sullivan added.

Sullivan was communicating a clear message to Israel’s government, days after a public rift opened between Biden and Israeli Prime Minister Benjamin Netanyahu over the mounting civilian casualties in Gaza.

Earlier this month, CNN reported that US officials expect the current phase of Israel’s ground operation to transition a lower-intensity, hyper-localized strategy that narrowly targets specific Hamas militants and leaders, possibly by January.

In a meeting on Thursday, Israel’s Minister of Defense, Yoav Gallant, told Sullivan the war in Gaza would last “more than several months,” according to Israel’s Ministry of Defense.

“It will require a period of time – it will last more than several months, but we will win and we will destroy them (Hamas),” Gallant said, according to a transcript of the meeting released on Thursday.

Sullivan made his comments prior to a planned trip to the West Bank on Friday as part of his push to demonstrate continued US support for Israel in its fight, while also urging the Israeli government to take meaningful steps to reduce civilian casualties in Gaza.

A US official told CNN that Sullivan would meet with President Mahmoud Abbas of the Palestinian Authority in Ramallah on the second day of his trip to the region. Sullivan previously met with Israeli Prime Minister Benjamin Netanyahu and other top government officials on Thursday.

Sullivan, the official said, “will discuss ongoing efforts to promote stability in the West Bank, including through efforts to confront terrorism, support for the Palestinian Authority Security Forces through the U.S. Security Coordinator for Israel and the Palestinian Authority, ongoing efforts to revamp and revitalize the Palestinian Authority, and initiatives to hold extremist settlers accountable for violence against Palestinians.”

Sullivan’s meeting with Abbas comes amid a disagreement between Biden and Netanyahu, who differ on whether the Palestinian Authority should have governing power in Gaza once Israel’s war with Hamas ends. The US has said the Palestinian Authority should assume governance responsibilities in Gaza after the end of Israeli military operations, but Netanyahu has repeatedly rejected that idea.

The Palestinian Authority is the Palestinian governing body in the West Bank. Hamas controls Gaza and presents itself as an alternative to the PA.

Vice President Kamala Harris’ national security adviser, Phil Gordon, previously met with Abbas and other Palestinian leaders last week.

Sullivan’s visit to Israel, his second since the deadly Hamas attack against the country on October 7, comes as Biden has become increasingly vocal about his desire to see the Israeli government take more concrete steps to eliminate civilian casualties in Gaza and called for Netanyahu to change his hardline positions.

Following a speech on prescription drug prices at the National Institutes of Health, the president was asked whether he wants the Israeli government to scale back its strikes against Hamas as it fights in Gaza.

“I want them to be focused on how to save civilian lives. Not stop going after Hamas, but be more careful,” Biden responded.

About 1,200 people, including Israelis and foreign nationals, were killed by Hamas militants during the group’s October 7 attack on Israel. More than 18,000 people have been killed in Gaza in the ensuing Israeli response, according to the Hamas-controlled Health Ministry.

This story has been updated with additional information.

CNN’s Sophie Jeong and Manveena Suri contributed to this reporting.