LONDON - A day after securing an end to the European Union's weapons embargo on Syria, Britain and France are facing criticism from Russia, and pressure at home and abroad, to show restraint before acting to arm the rebels seeking to oust Syrian President Bashar al-Assad.

Britain, along with France, scored a diplomatic victory in Paris on Monday, effectively blocking an attempt by other European nations to extend the regional embargo that has prevented them from sending weapons to help the Syrian opposition. Britain said it has no immediate intention to ship arms, and in Paris and London, Monday's decision was portrayed as a tool aimed at pressuring Assad to negotiate.

But the dropping of the embargo has opened a possible route for Britain and France, which have been leading the charge in the West for more support to the Syrian opposition, to act unilaterally should they choose to.

After the French intervention in Mali in January, Monday's move once again underscored the inability of the EU to forge a united front on major foreign policy issues. The repeal of the embargo was bitterly opposed by a number of European countries, including Austria. They fear that any arms sent to the rebels could fall into the hands of Islamist extremists within the Syrian opposition and lead to more regional spillover of the conflict.

In Washington, Obama administration officials voiced strong support for letting the embargo lapse, saying its end would contribute to the two-track policy pursued by supporters of the Syrian opposition: backing the rebels while pushing for a political settlement.

"We welcome the EU action," White House spokesman Jay Carney said.

At the same time, Carney and others said the administration opposes Russian shipments of arms, including sophisticated S-300 air-defense systems, to the Assad regime.

Russia denounced the EU action, saying it placed Europeans on the brink of supplying arms to a murky rebel force.

"You cannot declare the wish to stop the bloodshed on one hand and continue to pump armaments into Syria on the other hand," Sergei Ryabkov, the deputy foreign minister, said Tuesday at a news conference in Moscow.

In a commentary posted on the Russian Foreign Ministry website, spokesman Alexander Lukashevich said Moscow is concerned that the EU decision might persuade rebel groups not to join the Russian-American peace conference tentatively planned for June.

At the same time, Russia defended its decision to continue supplying air defense and anti-ship missiles to the Syrian regime.

Moscow's envoy to NATO, Alexander Grushko, told journalists that Russia would continue to honor its commitment to deliver S-300 missile systems. "We will fulfill the signed contracts," Grushko said. "Russia has been acting in total compliance with international law."