The increase was most dramatic in the use of suicide car bombs, a hallmark of Iraq’s branch of al-Qaeda.
“There is limited U.S. credible reporting in Syria, so there is a lot we do not know,” the official said. The official declined to talk about U.S. sources for the information, which are classified.
A look at the Syrian uprising one year later. Thousands of Syrians have died and President Bashar al-Assad remains in power, despite numerous calls by the international community for him to step down.
A steady stream of people went to his house while crowds gathered for the stadium memorial.
“Mandela taught us the power of action, but also ideas,” the president said, according to prepared remarks.
President Obama and the U.N. secretary general are among those scheduled to address the crowd.
Israel, Jordan and the Palestinian Authority sign a long-delayed pact for a $500 million desalination project.
Nonetheless, the administration has gradually widened its embrace of the rebels, despite a lack of information about their backgrounds and agendas in a country largely defined by its ethnic and sectarian divisions.
The administration has explored ways to expand support short of arming the rebels, officials said. Some “non-lethal” aid supplied by the United States, such as communications equipment, can be used by rebels to coordinate and direct attacks with sophistication approaching that of the Syrian army.
The rebels are still badly out-gunned, however. Some Arab nations are funneling weapons to the rebels, but they do not have anything like the air power or aerial defenses of what some analysts say is second only to Israel as the best military in the Middle East.
To date, the United States has also supplied $64 million in humanitarian help inside Syria and for refugees in neighboring countries, said Tommy Vietor, White House National Security Council spokesman.
The administration is still struggling to develop a clear understanding of opposition forces inside the country, according to U.S. officials. U.S. spy agencies have expanded their efforts to gather intelligence on rebel forces and Assad’s regime in recent months, but they are largely confined to monitoring intercepted communications and observing the conflict from a distance, said officials who insisted on anonymity to discuss operations in Syria.
“Obama has been very reluctant, because he sees this as a slippery slope,” said Joshua Landis, director of the Center for Middle East Studies at the University of Oklahoma and a specialist on Syria. “Once you get in there and back a winner, you have to make sure that they win.”
Greg Jaffe contributed to this report.