Attorney General Dick Thornburgh and a coterie of top aides headed to Europe Monday on an 11-day trip to meet with foreign law enforcement officials and to attend an anti-terrorism conference.

FBI Director William Sessions, traveling separately, will join Thornburgh at semi-annual meetings in Athens, Greece, of an international group seeking to reinforce cooperation against terrorism, Justice Department officials said.Thornburgh had scheduled the trip before he was designated by President-elect George Bush to remain in his post, but has taken steps to avoid the globe-trotting image sometimes attached to President Reagan's first two attorneys general, William French Smith and Edwin Meese, the officials said.