BOSTON — David Gray should be making his final preparations for his first Boston Marathon. Instead, he's stuck in hotel room in Brussels, Belgium, trapped in Europe by a massive ash cloud spewed from an Icelandic volcano that's caused hundreds of flight cancellations.

Gray is not the only runner in danger of not making it in time to run the 114th Boston Marathon on Monday. Boston Athletic Association officials say they have heard from about two dozen runners stranded in Europe, including Abdellah Falil, a Moroccan in the elite field who's waylaid in Paris.

Falil, who competed in the 10,000 meters at the Beijing Games, was supposed to arrive Wednesday, but now he's not expected until Saturday night at the earliest. The race is Monday.

Gray has tried everything to get out of Belgium. He's asked to be rerouted through Italy or Spain, figuring they were far enough south to avoid the ash cloud. But the only way he can get there is by train or rental car, and they are all booked.

"Boston is different," said Gray, a 41-year-old New Yorker and television commercial producer who's twice run the New York City Marathon. "It's not the biggest marathon in the number of runners as far as majors go, but as far as I am concerned, it's the best of the best, with the best runners, and it's a bit of a badge of honor to say you've run Boston."

He's also asked about flying out of Moscow, and going over the North Pole rather than the North Atlantic. All his efforts have failed.

"To have an act of God like this happen is really frustrating," said Gray, who had planned on meeting his wife and two young sons, who he has not seen in three weeks, in Boston.

"I was talking to my 3-year-old son, explaining about the volcano and why I wouldn't see him for a few more days, and he said, 'Daddy, why they can't they fix it?"'

Martin Cunningham, 47, of Bromley, England, said he has been waiting for a couple of days after British Airways sent him a tweet that his flight to Boston was canceled.

"I really set my heart on doing Boston after completing a marathon in Berlin last September," he said.

Cunningham said he has been training hard since December.

Late Friday, Cunningham said on Twitter that British Airways had canceled his Saturday flight and that he wouldn't be coming to Boston after all. "Game over," he tweeted.

The Boston Marathon isn't the only race affected by the volcano.

"We've got the exact same problem — runners can't make it to Vienna," said Andreas Maier, an organizer of Sunday's Vienna City Marathon.

And in soccer, Premier League referee Steve Bennett has been replaced for Saturday's Manchester derby between City and United after getting stranded in Romania at a training course.

He was due to fly back Friday. The Premier League said he was expected to referee the derby at Eastlands but has been replaced by Martin Atkinson.

In response to the flight delays, organizers in Boston have extended the traditional Sunday night check-in deadline, and may even allow check-in the day of the race.

"I've had bad luck traveling, but this is up there," Gray said.