Britain's opposition Labour Party has indicated it may not support even a watered down version of a government resolution on Syria.
Labour leader Ed Miliband said Thursday he is unwilling to give Prime Minister David Cameron a "blank check" for conducting possible future military operations against Syria.
He had earlier forced Cameron to back down on calls for an immediate strike in order to assess UN inspectors' evidence about a possible Syrian government chemical attack on its people.
Labour's position leaves the results of a parliamentary vote expected late Thursday in doubt. If approved, the measure would authorize possible strikes in principle but would require a second vote after the UN report.
The government says it plans to publish its legal advice on a possible attack Thursday.