LONDON — Increasingly flustered with the inability of the United Nations to deliver aid to war victims in Syria, Secretary of State John Kerry said on Thursday that the United States was considering ways to increase the delivery of aid without the consent of President Bashar al-Assad’s government.

“We are open to the idea of providing aid through any means that will get to the people who need it,” Mr. Kerry said after a meeting here on the Syria crisis that included his counterparts from 10 Western and Arab countries.

“We are very frustrated with the current process,” Mr. Kerry added. “It is not getting to people. It’s going through one gate, one entryway, and it’s going through Damascus and/or controlled by the Assad regime. That’s unacceptable. We need to be able to get aid more directly, and we’re going to work to do that.”

He took part in a meeting of the so-called Friends of Syria group, also known as the London 11, that opposes Mr. Assad’s government. The meeting was attended by Ahmad Jarba, the head of the moderate Syrian opposition.