WASHINGTON (Reuters) - A land border agreement between Israel and Lebanon implemented in phases could dampen the simmering and deadly conflict between the two countries, a senior adviser to President Joe Biden said on Thursday.

Attacks between Israel and Iran-backed Hezbollah militants in Lebanon have led to worries of a deeper war across the Middle East. The two sides have been engaging in regular exchanges of missile fire and airstrikes since the start of the war in Gaza last October.

"I'm not expecting peace, everlasting peace, between Hezbollah and Israel," Amos Hochstein, a senior adviser to Biden for energy and investment, said in an interview with the Carnegie Endowment for International Peace.

"But if we can reach a set of understandings and ... take away some of the impetus for conflict and establish for the first time ever, a recognized border between the two, I think that will go a long way."

Hochstein brokered an Israel-Lebanon maritime boundary agreement in late 2022, after two years of talks, that opened the way for both countries to develop natural gas and other resources in the region. Hochstein has been working on a demarcation of the land border between the two countries that could have a number of phases.

The first would be to allow for people in northern communities in Israel to return to their homes and those in southern communities in Lebanon to return to their homes, Hochstein said.

Part of that would require a strengthening of the Lebanese armed forces, including recruiting, training and equipping forces, Hochstein said without detailing how that would happen.

The second phase would involve an economic package for Lebanon, "making sure that the international community demonstrates to the Lebanese people that we're invested in them."

Lebanon's power grid, for example, only operates a few hours per day, at an enormous detriment to its economy. "We have a solution for that, we've put together a package that could create a solution that would take them to 12 hours of electricity in a ... short amount of time," Hochstein said.

The last phase would be a land boundary agreement between Lebanon and Israel, he said.

If politics and the economy are stabilized in Lebanon, it could help reduce Iran's influence there, he said.

"The ability of outside forces of any consequence to influence Lebanon will diminish dramatically," Hochstein said.

(Reporting by Timothy Gardner; Editing by Hugh Lawson)

By Timothy Gardner