More than 5,000 Syrians have died from President Bashar al-Assad’s butchery. The international community finally has a sense of urgency, but it has yet to come up with a strategy to end the killing. It needs to try harder.

There should be no illusions. This is an incredibly difficult problem. Most countries, the United States included, have rightly ruled out military intervention. Mr. Assad is determined to resist, no matter what the cost. The Syrian Army is far stronger and better armed than that of Libya’s under Col. Muammar el-Qaddafi. There is legitimate fear that a foreign intervention would unleash an even bloodier civil war and possibly spread beyond Syria’s borders.

The only hope is that the Syrian people are determined to resist and Mr. Assad’s isolation is growing. At a meeting in Tunis on Friday, more than 60 governments and organizations agreed to intensify diplomatic and economic pressure on the Syrian leader and vowed to find ways to support opposition forces trying to depose him.

On Monday, the European Union plans to freeze the assets of Syria’s central bank. The meeting called on all nations to impose additional sanctions, including travel bans on all of Mr. Assad’s cronies and a wider embargo on purchases of Syrian oil. But Syria still has far too many powerful protectors.

Russia and China have blocked any action at the United Nations Security Council. Russia and Iran are selling arms to Syria. The United States and Europe need to use all of their powers of persuasion and shaming to get Moscow and Beijing to cut all ties. Iran is obviously a lost cause.

At the meeting, countries also pledged millions of dollars worth of food and medicine to help people in Syria’s besieged cities. Officials suggested the aid could be distributed from border areas in Turkey, Jordan and, possibly, Lebanon. Mr. Assad is unlikely to let that happen.

Homs, Syria’s third-largest city, has been under a fierce government bombardment for three weeks. Scores of people have been killed in the shelling, and desperate residents are facing severe shortages of food and medical supplies. It is time for the United States and others to take a serious look at proposals by Turkey and others to create humanitarian corridors linking besieged communities to neighboring countries or safe zones along those borders. Both would require air cover and would be risky.

The meeting also called for the creation of a joint Arab League-United Nations peacekeeping force to be deployed if a cease-fire is reached. Kofi Annan, the former United Nations secretary general, has been appointed to pursue that solution. There is no sign whatsoever that Mr. Assad will cooperate.

The worsening violence — and the mismatch between the 200,000-member Syrian Army and ragtag rebel forces — has accelerated calls, especially from the gulf states, to arm the opposition. Some countries are already quietly doing that. The United States this week opened the door to the possibility. At a minimum, Washington and its allies should consider providing communications equipment, intelligence and military training.

This will amount to little if the opposition — divided along ethnic and sectarian lines — fails to unite and offer a credible vision of a post-Assad future in which the rights of all Syrians will be respected. The leader of one group, the Syrian National Council, offered encouraging words on Friday, but there is a very long way to go. The United States and its allies will have to work hard to help them get there. The horrors and the death toll keep mounting.