Defense Department spokesman George Little said Hagel met with Brahimi, U.N. special envoy for Syria, at the Defense Department and they efforts to find a political solution to the crisis in Syria.
"They also exchanged views on the military effectiveness of the Syrian opposition and the role its leaders might play in a political transition," Little said.
U.S. Ambassador to the United Nations Susan Rice described Brahimi's testimony before the U.N. Security Council in January as "grim." Efforts to find a solution at the Security Council have come to a dead end, she said.
Syrian civil war is in its third year. The United Nations estimates at least 70,000 Syrians have died in the conflict and more than 1 million people have become refugees.
Western officials are reviewing preliminary evidence that suggests Syrian forces may have used chemical weapons during the conflict. Hegel said the Defense Department was working with U.S. allies and various intelligence agencies to get a better understanding of the weapons claims.
The United Nations was invited to investigate claims by the Syrian government that rebel forces used chemical weapons. The Syrian government balked on the probe, however, amid concerns that investigators would broaden their investigation.