The Obama administration is struggling to convince a skeptical public that U.S. airstrikes against Syria are needed, two new polls say.

The results of a Pew Research survey released Tuesday show that 48 percent of Americans oppose U.S. military airstrikes against Syria in response to reports that the Syrian government used chemical weapons. Only 29 percent support such action, with 23 percent saying they're not sure.

Opinion among independents is similar, with 50 percent opposed to airstrikes and 29 percent in favor.

Republicans are more divided, with 40 percent opposing airstrikes while and 35 in favor.

The national survey of 1,000 adults found broad concern over the possible consequences of military action in Syria and little optimism it will be effective. Seventy-four percent of poll respondents say U.S. airstrikes in Syria are likely to create a backlash against the United States and its allies in the region, while 61 percent say it likely would lead to a long-term U.S. military commitment there.

Meanwhile, just 33 percent say airstrikes are likely to be effective in discouraging the use of chemical weapons, and 51 percent say they're not likely to achieve this goal.

In a Washington Post-ABC poll, 59 percent of respondents oppose U.S. airstrikes in Syria, while 36 are in favor.

The Post-ABC poll results, released Tuesday, show support for an airstrike would increase to 46 percent if U.S. allies such as Great Britain and France participated.