Several NATO countries like Germany and France have limited their troop contribution to peacekeeping and training missions in relatively safer areas of the country.

'The vulnerabilities to terrorist attack in Europe are at least as high as they are here in the United States,' Obama said. 'If you look at how Al Qaeda has operated, they consider the West to be one undifferentiated set of countries, and they will exploit whatever weaknesses are there.'

Meanwhile, Balkenende said he had accepted Obama's invitation to the attend the summit of the world's leading economies known as the Group of 20. The summit is set to take place in September in Pittsburgh, Pennsylvania to discuss the worldwide financial crisis.

The Netherlands is not a member of the G20.