Israeli Defence Minister Yoav Gallant has told visiting White House national security adviser Jake Sullivan that it will take several months to defeat Hamas in the Gaza Strip, Reuters reports.

Gallant said that for over a decade Hamas has been building its “infrastructure under the ground and above the ground” and that to destroy the group “it will require a long period of time — it will last more than several months, but we will win and we will destroy them.”

The two also discussed the need to return Israelis to their homes near the border with Lebanon after tens of thousands of people were displaced due to fighting with Hezbollah, according to statement from Gallant’s office.