JERUSALEM (Reuters) -- Israeli Prime Minister Benjamin Netanyahu agreed with the United States on Wednesday that Iran needs roughly a year to build a nuclear weapon, but stressed that Israel's initial concerns were focused on uranium enrichment.

At a joint news conference with US President Barack Obama, Netanyahu reiterated that Israel did not want to see Iran build up its stockpiles of enriched uranium, regardless of whether the Islamic Republic had decided to go on and build an atomic bomb.

"If Iran decides to go for a nuclear weapon ... then it will only take them about a year," Netanyahu said, adding: "Iran gets to an immunity zone when they get through the enrichment process in our view."