US President Barack Obama has pledged to break North Korea's “pattern of provocative behavior,” urging Pyongyang to refrain from carrying out a planned satellite launch. During a Sunday news conference in the South Korean capital of Seoul, Obama also said that China has turned “a blind eye to deliberate provocations” of North Korea’s nuclear issue and that it should pressure Pyongyang to abandon its plan to launch the rocket-powered satellite next month. Obama's rhetoric follows Pyongyang’s announcement last week about its plan to carry out a satellite launch in April. The US president said the move could not only jeopardize a food aid deal and future disarmament talks, but may also lead to tighter sanctions against North Korea. Pyongyang says the satellite launch is a legitimate and peaceful space program. The country has invited international space experts and journalists to witness the launch. Earlier on Sunday, Obama visited a US base on the edge of the Demilitarized Zone (DMZ) on the North-South Korean border and peered long across North Korea’s border. Obama is in Seoul to attend the Nuclear Security Summit 2012. He will join more than 50 other world leaders on Monday for a follow-up to the summit that was organized in Washington in 2010 to help combat what “the threat of nuclear terrorism.”