U.S. Attorney General John Ashcroft and EU justice officials agreed Thursday to improve the trans-Atlantic flow of intelligence to help track down terrorists and prevent attacks. Among new measures agreed during several hours of meetings here was the exchange of liaison intelligence officers between the continents. The United States will send an agent from the Federal Bureau of Investigation to the European police agency Europol in The Hague, Netherlands, and the EU will post two agents in Washington, said Antonio Vitorino, the EU justice and home affairs commissioner. The discussions came at the start of two days of talks between EU justice and internal affairs ministers in the Netherlands, which currently holds the EU presidency.