BRUSSELS - The European Union expressed serious concern on Tuesday about Israel's decision to approve new settler homes in the occupied West Bank, calling them an obstacle to peace and adding to international condemnation.

Israel approved on Monday the building of 455 settler homes, a move opposed by its U.S. ally and Palestinians but which may pave the way for a construction moratorium sought by Washington.

The European Union expresses its serious concern over Israel's approval of additional settlement construction, a statement from the Swedish EU presidency said.

Settlements are illegal under international law and constitute an obstacle to peace. The European Union reiterates its call on Israel to immediately end settlement activities, including in East Jerusalem and including natural growth, and to dismantle all outposts erected since March 2001, it said.

The decision to authorize the housing units was widely seen in Israel as an attempt by Prime Minister Benjamin Netanyahu to mollify pro-settler members of his government and Likud party before agreeing to a freeze of construction starts.

A Defense Ministry list showed the homes would be erected in areas Israel says it intends to keep in a future peace deal with the Palestinians.

Palestinian chief negotiator Saeb Erekat said Israel's decision further undermined any belief that it was a credible partner for peace.

(Reporting by David Brunnstrom; Editing by Louise Ireland)