The European Union and the United States agreed that addressing global warming is a pressing issue. President George W Bush acknowledged the importance of convincing Russia about the necessity of a missile shield in Europe. During a White House summit, Bush, German Chancellor Angela Merkel, and European Commission President Jose Manuel Barroso reaffirmed their commitment to reaching a global trade agreement. They also continued to pressure Iran to abandon its nuclear weapons program. Merkel, on her first visit to Washington as the rotating EU president, emphasized the importance of addressing global climate change ahead of the Group of Eight summit in Germany in June. During a press conference held in the Rose Garden, the European representatives expressed their belief that progress had been achieved on the issue, even though no specific actions were identified for the EU and the United States to jointly tackle the problem. Barroso stated, "I am pleased to see progress being made in this meeting. We all acknowledge the existence of a significant global threat and the necessity to decrease emissions. It is agreed that collaboration between our nations is essential." Bush, who was criticized for being slow to acknowledge climate change as a problem, emphasized that any agreement between the United States and Europe would have limited impact without the involvement of developing countries like China. He argued that even if the US drastically reduced its greenhouse gas emissions, China could easily offset that reduction in a short amount of time. However, Merkel countered by asserting that developed countries must take the lead in reducing carbon emissions. She stated that if technologically advanced countries do not take action, it will be difficult to persuade others to do so, ultimately leading to a failure in reducing worldwide CO2 emissions. The leaders of the US and EU met amidst criticism from Russia regarding US plans to deploy a missile shield in Eastern Europe. Russian President Vladimir Putin vowed to take action against the system. President Bush mentioned that German Chancellor Angela Merkel had previously expressed concerns about the missile shield and suggested that he explain his vision to Putin. Bush sent Defense Secretary Robert Gates to Moscow to offer Russia the chance to be part of the shield, which is aimed at countering terrorism rather than restarting the Cold War. Bush stated that this dialogue aims to clarify intentions and show Russia that the US is not an enemy, but a friend.