The question is whether or not PMC soldiers are as accountable for their war zone actions. A common argument for using PMCs (used by the PMCs themselves), is that PMCs may be able to help combat genocide and civilian slaughter where the UN or other countries are unwilling or unable to intervene. In February 2002, a British Foreign and Commonwealth Office (FCO) report about PMCs noted that the demands of the military service from the UN and international civil organizations might mean that it is cheaper to pay PMCs than use soldiers. Yet, after considering using PMCs to support UN operations, the UN Secretary General, Kofi Annan, decided against it. In October 2007, the United Nations released a two-year study that stated, that although hired as "security guards", private contractors were performing military duties. The report found that the use of contractors such as Blackwater was a "new form of mercenary activity" and illegal under international law. Many countries, including the United States and the United Kingdom, are not signatories to the 1989 United Nations Mercenary Convention banning the use of mercenaries. A spokesman for the U.S. Mission to U.N. denied that Blackwater security guards were mercenaries, saying "Accusations that U.S. government-contracted security guards, of whatever nationality, are mercenaries is inaccurate and demeaning to men and women who put their lives on the line to protect people and facilities every day." History Europe Classical era Greek mercenaries in Persian Empire Xerxes I, king of Persia, who invaded Greece in 484 BC employed Greek mercenaries. In Anabasis, Xenophon recounts how Cyrus the Younger hired a large army of Greek mercenaries (the "Ten Thousand") in 401 BC to seize the throne of Persia from his brother, Artaxerxes II. Though Cyrus' army was victorious at the Battle of Cunaxa, Cyrus himself was killed in battle and the expedition rendered moot. Stranded deep in enemy territory, the Spartan general Clearchus and most of the other Greek generals were subsequently killed by treachery. Xenophon played an instrumental role in encouraging "The Ten Thousand" Greek army to march north to the Black Sea in an epic fighting retreat. The Sileraioi were a group of ancient mercenaries most likely employed by the tyrant Dionysius I of Syracuse. In 378 BC the Persian Empire hired the Athenian general Iphicrates with his mercenaries in the Egyptian campaign. The Mania, who was a sub-satrap, used Greek mercenaries in order to