Republican presidential nominee Mitt Romney has opened a new front in his critique of President Obama's foreign policy, assailing the president's lack of leadership on Syria and calling for the United States to arm the Syrian opposition.

In a statement released on Tuesday, Romney lauded the decision by the United States and other countries to expel Syrian diplomats, earlier this week. But he sharply criticized the Obama administration for not acting decisively to stop the spiraling bloodshed as President Bashar al-Assad continues to violently stifle a popular uprising.

Expelling the diplomats only underscores the need for more assertive measures to end the Assad regime, Romney said in the statement. President Obama's lack of leadership has resulted in a policy of paralysis that has watched Assad slaughter 10,000 individuals. 

The charge fits into Romney's broader attempt to depict Obama as timid and ineffective when it comes to handling antagonistic or brutal foreign regimes. He has characterized Obama's approach toward Iran as one of appeasement and accommodation and slammed Obama for telling Medvedev of Russia -- a country Romney called our No. 1 geopolitical foe -- that he would have more flexibility after the presidential election to work on arms control.

Romney's call to arm the Syrian dissidents also breaks with some members of the Republican party. A trio of senators led by John McCain has long called for more aggressive efforts to bolster the Syrian resistance, charging that the United States has a moral imperative to intervene.

But most lawmakers have taken a more cautious approach, wary of being dragged into another complex and costly Middle Eastern war just as American troops exit Iraq and Afghanistan. At a recent Congressional hearing on Syria, Defense Secretary Leon Panetta found support on both sides of the aisle for his warnings about the limits of military force.

The White House has promised to aid the Syrian rebels by sending them communications equipment but has stopped short of offering munitions, seeking instead to find a diplomatic solution. Wary observers note that the Syrian opposition is a nebulous movement riven by internal divisions and sectarian tensions, and the Obama administration appears reluctant to arm fighters it does not know.