Danny Lopez, British Consul-General in New York has told Daybreak that the Consul has no idea how many Brits are stranded in the States.
Mr Lopez said: "We don't have any numbers or figures right now. Over the past 48 hours we've only had 14 calls from Brits wanting more information."
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The 10K and half-marathon races take place almost exactly a year after Salman Abedi killed 22 in his attack at an Ariana Grande concert.
Dmitrios Pagourtzis also had several kinds of homemade explosive devices but they were not capable of detonating, county officials said.
After early mist clears, most parts of England and Wales will have another fine, warm day with plenty of sunshine.