Arrows have left the Spa-Francorchamps track in Belgium this weekend, blaming legal complications for stalling a claimed deal with an American investor.

But the sport's governing body, the FIA, has demanded a more detailed explanation.

This is because Arrows have been beset by financial problems this season and the FIA believes the team may be effectively insolvent.

If a team miss a race because of insolvency, they lose all their rights in F1 - including financial benefits and their entry into the championship.

An FIA spokesman said: "We've asked Arrows for a detailed explanation about their state of health following certain decisions over the past few weeks. We will then decide which position to adopt.

"[Punishment] could go from a simple fine to being banned from the [F1] circuit," the spokesman added.

"But before any decision is taken we must consider the large number of people who are employed with the team."

Arrows said on Wednesday that they had signed a pre-contractual agreement with an American investor for a deal that would save the debt-ridden team.

But in a statement on Friday they said that the deal had not yet been completed.

"The team has been advised to do nothing that could jeopardise the successful completion of the transaction so will not race in Sunday's Belgian Grand Prix," Arrows said.

The man behind the deal that could save the future of the team is a wealthy American called Cal Smith, BBC Sport Online exclusively revealed on Thursday.

The billionaire, who is in his 80s, made his fortune in mining, a source said.

The source added that this was a serious deal that would save the team if it came off, but there remains deep scepticism about it within F1.

Some insiders believe that it was an elaborate ruse to prevent Arrows falling foul of the Concorde Agreement, the secret covenant that governs F1.

'Extremely hard work'

They have already missed the Hungarian GP this month because of their financial problems - and they made no attempt to qualify for the French race in July.

The Arrows statement said: "The legal teams are still working through the detailed documentation that supports the sale of Arrows.

"Professional advisors on all sides have been working extremely hard all week to finalise the deal in time for this weekend.

"Unfortunately, due to the sheer amount of paperwork involved, the process cannot be completed by close of business [on Friday]."

The team announced on Friday that they had signed a Heads of Agreement with their unspecified "American investor".

On Thursday, former F1 team owner Craig Pollock admitted that he had lost out in his attempt to buy Arrows.

The Scot was the front-runner to take over the trouble team two weeks ago.

Pollock said: "My interest in Arrows is officially finished. That's it."

Arrows have struggled financially since July, when a London High Court injunction prevented team owner Tom Walkinshaw from selling key assets and taking on new investors.

The injunction was won against Walkinshaw by Arrows' chief shareholder, the investment bank Morgan Grenfell, which appears to be involved in talks with the new investor.