It represents a big increase on the last numbers given by the company, which covered from February to August 2016, although the data overlaps.

Twitter has faced pressure to do more to stop groups such as so-called Islamic State from using its platform.

Last year, MPs said it had become a "vehicle of choice" for spreading extremist propaganda on the internet.

In Twitter's latest transparency report - which covers the period from 1 July to 31 December 2016 - it said internal measures to tackle the issue had improved.

It said that 74% of the accounts it had suspended had been "surfaced" by internal, proprietary spam-fighting tools.

That compares with a third in its previous figures.

It also said it had shut a total of 636,248 accounts for promoting terror since August 2015, when it first began tracking numbers.

That is up from a total of 355,000 reported last summer.

'Recruiting platform'

In August last year, the Home Affairs Committee accused Twitter - alongside Facebook and YouTube - of "consciously failing" to combat the promotion of terrorism and extremism on their sites.

The MPs also said Twitter had become a "recruiting platform" for terrorism, and that its rate of suspending accounts at the time was "a drop in the ocean".

Prof Tahir Abbas, a senior research fellow at the think tank Rusi, told the BBC: "Twitter is a powerful instrument in the hands of those who would wish to spread fear and hate but, crucially, mobilise and enable people to carry out actual acts of terrorism.

"But it is heartening to know that both effort and success rates are improving."

He added: "This is especially important, as it is clear that while there are takedowns of various sites... there is a tendency for them to re-emerge elsewhere."