Achieving a multinational arms-control treaty governing the use of cyber-weapons may be impossible because groups unaffiliated with governments wouldn’t honor it, Admiral Michael Rogers, the director of U.S. National Security Agency, told lawmakers.

Terrorist groups such as Islamic State aren’t interested in stability and want to “tear the status quo down,” Rogers told the Senate intelligence panel during a hearing on Thursday.

The U.S. may, however, be able to work directly with countries like China and Russia to develop acceptable practices when it comes to Internet activity, Rogers said. “I don’t know if an arms control agreement is the right answer,” Rogers said. “I think we can get to the idea of norms.”

Rogers’ comments come on the eve of a historic summit by President Barack Obama and his Chinese counterpart, Xi Jinping. The countries are trying to agree to a code of conduct for cyber security operations, such as prohibiting attacks vital computer networks during peacetime.

Some senators said the U.S. needs a better strategy to deter increasingly sophisticated and dangerous cyber-attacks.

“The cyber war has started and we are in the cyber war with our hands tied behind our back,” said Senator Angus King, an independent from Maine.

U.S. officials and private cyber security experts believe a breach of the U.S. Office of Personnel Management’s computer system disclosed earlier this year, which compromised data on some 21.5 million individuals, was carried out by the Chinese government.