Leaders Begin What Many Expect to Be Divisive Final Round of Negotiations Over Constitution for European Union

European leaders sat down Saturday to what many expect to be divisive final round of negotiations over a constitution for the European Union, a document meant to ready the bloc for expansion next year. Leaders from the 15 EU nations and the 10 that are set to join the club next May arrived under heavy security at Rome's Palazzo dei Congressi to launch the negotiations on the new blueprint. Police cordoned off a 2 1/2-mile zone around the meeting hall. Security was tight across the capital as authorities braced for 30,000 expected anti-globalization protesters. Italian media reported that some 4,000 police were being used as part of the security clampdown. Tensions already were high in Rome after a small package exploded at a Labor Ministry building Thursday; two others were sent to offices but did not blow up. No injuries were reported. Italian Premier Silvio Berlusconi, whose country holds the EU presidency, has urged his colleagues to avoid a wholesale renegotiation of the constitutional text that has emerged from 18 months of preliminary negotiations. That draft foresees an EU president, a foreign minister, a structured defense policy and provisions to make it more difficult to wield vetoes that cause bureaucratic gridlock. It calls for an EU executive of only 15 members, denying each state the automatic right to one European Commissioner. Austria, Finland, and those set to join the club next year Hungary, Slovenia, the Czech Republic, Malta and Lithuania sent Berlusconi a letter on the eve of the summit demanding major revisions. The constitution, they said "should respect the principles of equality" of EU nations large and small.