(Al Jazeera English News Headlines: May 26, 2010) U.S. Secretary of State Hillary Clinton issued a stern warning to North Korea over its sinking of a South Korean warship and other provocations. Oil giant BP is looking to try a new technique, called "top kill," to seal the disastrous oil leak in the Gulf of Mexico. Left-wing Maoist fighters, known as Naxalites, have stepped up their attacks against government targets in India, but it is Indian civilians that are suffering. The space shuttle Atlantis has made its last landing, and only two more flights are planned for sister shuttles Discovery and Endeavor as NASA retires its space shuttle program.