Arab League Secretary-General Amr Moussa said Friday it will become impossible to establish a Palestinian state unless Israel halts settlement construction in the West Bank immediately. Moussa said the population in the West Bank is changing rapidly as the Israelis continue to build, making a two-state solution more unlikely as time goes by. "If they continue this policy of changing the demographic composition ... of the territories, it will be practically impossible to establish a Palestinian state - a viable Palestinian state," Moussa said. "This is the point that makes or breaks." His comments came a day after US President Barack Obama met with Palestinian Authority President Mahmoud Abbas and also called for a halt to the settlements, while urging the Palestinians to be more accepting of their Israeli neighbors. Israel, however, has rejected US requests to freeze the construction in the West Bank, a territory that would make up the Palestinian state, along with the Gaza Strip, as part of a broader peace deal. Moussa expressed cautious optimism in the Obama White House, noting that its approach toward Israel appears to be more "blunt" than that of preceding administrations. He said US Secretary of State Hillary Rodham Clinton's strongly worded call for a stop to the settlements earlier this week was "a welcome change." Clinton said Wednesday the halt to construction should include "natural growth." Israel uses that term for new housing and other construction that it says will accommodate the growth of families already living in existing settlements. Moussa also welcomed Obama's upcoming trip to Egypt, where he plans to discuss his country's outreach to Muslims around the world and contributions of Muslims in the United States in a speech June 4. Obama also said he would discuss the broader need for peace in the Middle East and common understanding among nations.