A plan for 272 new homes in West Bank settlements was approved on the eve of US Secretary of State John Kerry's departure Monday, Israel's Peace Now movement said.
Israel had been expected to announce new settlement plans alongside the release of Palestinian prisoners last week -- as it did during previous releases -- in a bid to ease the concerns of hardliners as it engages in US-brokered peace talks.
Peace Now said the construction of 250 homes at Ofra and 22 at Karnei Shomron was approved by the Israeli military administration charged with the settlements.
"Building could begin rapidly," the anti-settlement group said in a statement.
"A government seeking a two-state solution will not worsen the conflict by building in the settlements, especially those with no chance of remaining under Israeli sovereignty" in the event of a peace deal with the Palestinians, it said.
Ofra and Karnei Shomron are "both isolated settlements in the heart of the West Bank," Peace Now said.
A defence ministry official told AFP the planned building work was announced last October.
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"Sunday's publication is only the second of four necessary steps before building work can begin," the official said on condition of anonymity, adding that obtaining the necessary permits will take "months."
Prime Minister Benjamin Netanyahu also told members of his Likud party on Monday that he did not intend to dismantle settlements in the West bank as part of peace talks with the Palestinians, the private television station Channel 10 reported.
Asked by party hardliners about any possible concessions in the talks, Netanyahu said he would make no "territorial concession" in the Jordan Valley, the occupied West Bank or in annexed east Jerusalem, the station reported.
Kerry left Israel on Monday after his tenth trip to the region since last March, insisting progress had been made despite failing to reach a framework to guide Israeli-Palestinian peace talks.
Israel freed 26 long-serving Palestinians last week, the third of four tranches it plans to release in line with commitments made as part of the latest peace talks.
The first two releases were accompanied by the announcement of new settlement construction plans in the occupied West Bank and annexed east Jerusalem.
Some 350,000 Jewish settlers live in West Bank settlements, in addition to another 200,000 Israelis settled in occupied and annexed east Jerusalem.
The international community considers the colonisation of occupied land to be illegal, and the Palestinians have long viewed settlement construction as a key obstacle to reaching a peace agreement.