Her first stop is the Czech Republic for talks on energy policy in a country heavily dependent on Russian fuel.
Clinton joins NATO foreign ministers in Brussels to discuss Turkey's request for Patriot missile assistance. Violence is raging in neighboring Syria, which is believed to have several hundred ballistic surface-to-surface missiles capable of carrying chemical warheads - a particular concern for Turkey, a NATO member.
On Friday, NATO said it will deploy the Patriots within weeks after the move is approved.
Clinton also is to meet Pakistan's foreign minister, Hina Rabbani Khar.