The negative vote in Britain’s Parliament was a heavy blow to Prime Minister David Cameron, who had pledged his support to Obama and called on lawmakers to endorse Britain’s involvement in a brief operation to punish the government of President Bashar al-Assad for apparently launching a deadly chemical weapons attack last week that killed hundreds, administration officials said Thursday.

The vote was also a setback for Obama, who, having given up hope of getting United Nations Security Council authorization for the strike, is struggling to assemble a coalition of allies against Syria.

But administration officials made clear that the eroding support would not deter Obama in deciding to go ahead with a strike.

Pentagon officials said that the Navy had now moved a fifth destroyer into the eastern Mediterranean Sea. Each ship carries dozens of Tomahawk cruise missiles that would probably be the centerpiece of any attack on Syria.

Even before the parliamentary vote, White House officials said, Obama decided there was no way he could overcome objections by Russia, Syria’s longtime backer, to any resolution in the Security Council.

Although administration officials cautioned that Obama had not made a final decision, all indications suggest that a strike could occur soon after United Nations investigators charged with scrutinizing the August 21 attack leave the country. They are scheduled to depart Damascus on Saturday.

Hundreds of people were killed and scores of others were injured in a chemical attack in the Damascus suburbs of Ain Tarma, Zamalka and Jobar on August 21.

The foreign-backed opposition has blamed the Syrian government for the deadly attack.

The Syrian government, however, has vehemently denied the accusations, saying the chemical attack was carried out by the militants themselves as a false-flag operation.

NTJ/BA