By Paul Reynolds BBC News Online world affairs correspondent

Signs are growing that the Bush administration is gearing up for a decision at the end of the month or in early February on whether to go to war against Iraq.

And tensions are rising between the United States and other members of the Security Council led by France and Russia who want Washington to follow the lead of the weapons inspectors themselves and give them more time to do their work.

Key players remain unconvinced of the need to attack Iraq

Britain is increasingly in a difficult position.

Mr Blair's recent comments have swung him behind the George Bush line but he has also said that the inspectors must be given "time and space".

After a meeting with Hans Blix, the chief UN weapons inspector, on Friday his spokesman pointedly mentioned how much he strongly supported the inspectors' work.

US rhetoric

The way to war is being signposted by an increase in the American rhetoric, which is significant even allowing for the fact that at this stage you would expect the pressure on Saddam Hussein to be maintained.

The US says it will provide proof to back its case

The Secretary of State, Colin Powell, has told journalists from countries which have just joined the Security Council that "a persuasive case will be there at the end of the month that Iraq is not co-operating [with the inspectors]".

The discovery of 12 chemical warfare shells does not make the American case, but it is being used to help it.

The White House spokesman, Ari Fleischer, who picks his words carefully, said it was "proof that he [Saddam Hussein] has not disarmed".

One can expect the United States (and maybe Britain) to start making a much more vigorous case at some stage.

To convince the many doubters, they need to go beyond assertions into evidence stronger than the chance discovery of a few rockets.

Key junctures

Remember, though, that Security Council resolution 1441 does not require that actual weapons of mass destruction have to be found in Iraq before Iraq is in breach.

The resolution says that a failure to co-operate is the key and the United States has claimed a right to make that judgment itself. It might do so.

There is a rush of meetings and events at the end of January:

• The Security Council will be briefed by the weapons inspectors on 27 January. The chief inspectors are already saying that their task should not be hurried.

• President Bush makes his State of the Union address to Congress on 28 January.

• The Security Council meets again on 29 January and the US might press for a declaration that Iraq is in non-compliance.

• It might even try for a resolution authorising military action though its chances of getting one in the absence of firm evidence of Iraqi deception are low.

• George Bush meets Tony Blair at Camp David on 31 January.

It is awkward for Mr Blair to be seeing the president at the end of the sequence as he would have less chance of influencing any decisions.

If he protests, then Mr Bush might delay taking the final step until he has seen the one major ally who is likely to stand by him.

There is also a meeting of foreign ministers at the Security Council on 20 January to discuss international terrorism, a chance therefore to swap notes.

The British Foreign Secretary, Jack Straw, will see Mr Powell in Washington later in the week.

Warning from history

Meanwhile, Saddam Hussein has made a speech in which he compares the Americans to the Mongols who attacked Baghdad in 1258.

The US build-up has not weakened Iraq's defiance

He says that they will be forced to "commit suicide" at the gates of the city.

The problem with this analogy, as anyone in the Arab world knows, is that the Mongols under their general Hulegu, not only attacked Baghdad but captured and sacked it before going on to lay waste to much more of Arab civilisation.

They thus ended Baghdad's golden century as the centre of Islamic culture and learning.

Also destroyed was the Abbasid Caliphate, which ruled across the Islamic world from Baghdad.

The Caliphate, incidentally, is what the followers of Osama bin Laden would like to reconstitute.

The lessons for Saddam Hussein from history are not very good.