European airports have tightened security checks on US-bound flights today after a man tried to set off an explosive device on a flight between Amsterdam and Detroit.
The Dutch National Coordinator for Counterterrorism said in a statement that US authorities had asked airlines worldwide to take additional security measures for flights to the United States.
Security at Amsterdam's Schiphol Airport had been tightened, it said.
In Britain, airports operator BAA said the Department of Transport had issued a notice to all British airport operators to tighten security.
"Passengers travelling to the United States should expect their airline to carry out additional security checks prior to boarding," BAA said in a statement, adding that passengers should leave more time to check in.
In Brussels, Jacques Barrot, vice-president of the European Commission in charge of justice, freedom and security, said the EU executive was in contact with all relevant authorities to make sure rules and procedures were being followed in Europe.
"I am horrified by the attempted terrorist attack on a flight between Amsterdam and Detroit on Christmas Day," he said. "This incident shows once again that vigilance is necessary at all times in the fight against terror."
Nigerian Vice President Goodluck Jonathan has ordered the country's security agencies to investigate the attempted attack.
"While steps are being taken to verify the identity of the alleged suspect and his motives, our security agencies will cooperate fully with the American authorities in the ongoing investigations," the government said in a statement.
USofficials said a Nigerian man linked to al Qaeda tried to set off an explosive device aboard a US passenger plane as it approached Detroit on Friday, but was overpowered by passengers and crew.