Two men arrested in Texas as part of the investigation into the US terrorist attacks have been named by police this evening.
Mr Ayub Ali Khan and Mr Mohammed Jaweed Azmath were detained by police as they travelled on a train from St Louis, Missouri. They have been taken to New York for questioning.
Justice department sources say they had been on a flight from Newark to San Antonio, Texas, on Tuesday when it was forced to land at St Louis because of the immediate ban on flights in the aftermath of the attacks, CNN reported.
They had taken the train to San Antonio after landing in St Louis, and were detained for carrying box-cutters and having no legal identification.
One man arrested in New York's John F Kennedy airport has been held as a "material witness", a legal procedure which allows him to be held because of the likelihood he knows something which can help the investigation.
US officials continue to believe would-be terrorists are still at large in the country and have not ruled out the possibility of more attacks.
One official told CNN: "There is reason to believe not all the perpetrators are dead or in jail."
And Senator Joe Biden, a member of the Senate's intelligence committee, said it was apparent that several cells had worked to plan and co-ordinate the four attacks.
Police are looking for people who provided homes, credit cards, cars, mobile phones and laptop computers to the men. US police made their first arrest in their investigation of this week's terrorist attacks, detaining a suspect in New York thought to have ‘crucial’ information.
The FBI has received over 36,000 leads and has issued hundreds of subpoenas. It released the identities yesterday of the 19 hijackers.
The FBI said it was still investigating whether more terrorists might be at large and were searching for 100 people for questioning.
A list of more than 100 people has been distributed to thousands of local police departments, the Federal Aviation Administration, border patrols and FBI field offices, said Attorney General Mr John Ashcroft.
"We believe they may have information that could be helpful to the investigation," said Mr Ashcroft.
Nine people arrested earlier in John F Kennedy International and LaGuardia airports in New York have been released.
AP/PA