Thirty Israeli couples are on a waiting list to move into the Kfar Tapuah settlement, which teems with children on the hilltops south of Nablus. Some on the list grew up here. But there is not an apartment available for sale or rent, or even a stifling trailer to be had. If Israel built all the housing units already approved in the nation's overall master plan for settlements, it would almost double the number of settler homes in the West Bank, according to unpublished official data provided to The New York Times. The decision of whether to build, or how much, goes to the heart of the tensions between the administrations of Prime Minister Benjamin Netanyahu of Israel and President Barack Obama, an unaccustomed and no-budge conflict between Israel and the United States. Washington is standing firm against all increased settlement activity in the West Bank, including what Israel argues is necessary to accommodate what it terms 'natural growth.' That term has been defined vaguely by Israeli officials, meaning for some that settlements should expand to accommodate only their own children. But Netanyahu, of the conservative Likud Party, made clear his own wider position on Monday. He said that while Israel would not allow new settlements and that some small outposts would be removed, building within the confines of established settlements should go on. Israel 'cannot freeze life in the settlements,' he said, describing the American call as an 'unreasonable' demand. And, in fact, whatever the U.S. demands and Israeli definitions, the reality is that no full freeze seems likely. The issue is, in part, political: Netanyahu is trying to hold together a fractious coalition, including parties that favor settlement building and oppose the establishment of a Palestinian state. He must contend with an aggressive settler movement, emboldened by support from every Israeli government for decades and determined to continue building, if necessary through unofficial means. 'It is important for the world to know we won't stop,' said Doron Hillel, 29, the settlement council head and one of the first children born there after it was founded about 30 years ago. 'These decrees make things difficult, but they strengthen us. We will continue to build and grow.' A partial freeze has been in place for several years, but settlers have found ways around the strictures. Twenty trailer homes have been assembled in Kiryat Arba, near Hebron, for young families over the past year. The Samaria Council in the northern West Bank has brought 150 trailers. Thousands of permanent houses have been illegally constructed within existing settlements, and settlers have recently bulldozed new roads through fields to link up the outposts. Critics argue that successive Israeli governments have turned a blind eye to this construction and have contributed more broadly to settlement growth. The settlers' annual population growth, at 5.6 percent, far outstrips the Israeli average of 1.8 percent. But official data from the Central Bureau of Statistics of Israel shows that while some two-thirds of that is a 'natural' increase, as defined by settler births in relation to deaths, one-third stems from migration. There is also a disproportionately high level of state-supported building in the settlements compared with most regions of Israel. And many critics of the settlement movement dispute the notion that settlers' children have an absolute right to continue living in their parents' settlement. 'A newborn does not need a house,' said Dror Etkes of Yesh Din, an Israeli advocacy group that fights for the rights of Palestinians in the occupied territories. 'It is a game the Israeli government is playing' to justify construction, he said. Underlining the competing pressures on Netanyahu, extremist settlers rioted Monday in various parts of the northern West Bank, stoning Arab vehicles, burning tires and setting fields alight, according to a witness and the police. They were protesting the government's recent actions against some tiny outposts. Several Palestinians were wounded. Six Israeli settlers and a rightist member of Parliament were arrested and later released. The Israeli population of the West Bank, not including East Jerusalem, has tripled since the Israeli-Palestinian peace process started in the early 1990s, and it approaches 300,000. The settlers live among 2.5 million Palestinians in about 120 settlements, which much of the world considers a violation of international law, as well as in dozens of outposts erected without official Israeli authorization. Israel argues that the settlement enterprise does not violate the law against transferring populations into occupied territories. According to the newly revealed data, about 58,800 housing units have been built with government approval in the West Bank settlements over the past 40 years. An additional 46,500 have already obtained Defense Ministry approval within the existing master plans, awaiting nothing more than a government decision to build. The data was compiled in recent years by a retired brigadier general, Baruch Spiegel, at the request of the defense minister of the time, Shaul Mofaz. The Defense Ministry has long refused to make the data public, but it has since been leaked and obtained by nongovernmental groups. Etkes analyzed the master plans in the Spiegel data, together with a colleague from Bimkom, an Israeli group that focuses on planning and social justice. Under international pressure, construction in the settlements has slowed but never stopped, continuing at an annual rate of about 1,500 to 2,000 units over the past three years. If building continues at the 2008 rate, the 46,500 units already approved would be completed in about 20 years. In Kfar Tapuah, a group of young Israelis who grew up there decided about six years ago that when they got married, they would stay. The population has more than doubled since then, to 150 families from 60. As in other West Bank settlements, nobody counts individuals here: The rate of new births makes that impossible. Revitalized from within, the community also attracted young couples from other settlements and from cities in Israel who were seeking a lifestyle that combined relatively cheap suburban comfort with the national-religious ideal of settling the land. Kfar Tapuah has a reputation as an extremist settlement, having become a base for the followers of the virulently anti-Arab Rabbi Meir Kahane after he was assassinated in 1990. It now seems overrun by young children. A $150,000 playground recently went up, a second kindergarten just opened and a third is planned. 'This is our land from the beginning of days,' said Aviva Herzlich, 67, most of whose ten children and more than 40 grandchildren live in and around the settlement. 'We do not have anywhere else.' 