The volcanic ash cloud that has disrupted the travel plans of hundreds of thousands in Europe and around the world has also affected the President of the United States.
President Obama has canceled his trip to Poland to attend the funeral of President Lech Kaczynski, who died along with his wife and 94 others in a plane crash in Russia last week.
In a statement released by the White House this afternoon, Mr. Obama said, "I spoke with acting President Komorowski and told him that I regret that I will not be able to make it to Poland due to the volcanic ash that is disrupting air travel over Europe.
"Michelle and I continue to have the Polish people in our thoughts and prayers, and will support them in any way I can as they recover from this terrible tragedy.
"President Kaczynski was a patriot and close friend and ally of the United States, as were those who died alongside him, and the American people will never forget the lives they led."
The cloud of ash, which can cause jet engines to fail, has forced airspace over much of Europe to be shut down.
Several countries have already announced their delegates will not be able to attend Sunday's state funeral in Krakow, including Egypt, Macedonia, India, Japan, Mexico, New Zealand, Pakistan, South Korea, Spain and Sweden.