Russia will work with the United States to locate cyber criminals, the head of the FSB security service said on Wednesday, a week after the countries’ leaders agreed to step up cooperation in certain areas.

FSB chief Alexander Bortnikov said the security agency would follow agreements reached by presidents Vladimir Putin and Joe Biden in discussions about cybersecurity issues at a summit last week in Switzerland, their first face-to-face meeting since Biden took office in January.

“We will work together (on locating hackers) and hope for reciprocity,” the RIA news agency quoted Bortnikov as saying at a security conference in Moscow.

Another senior official said Moscow was awaiting an answer from Washington on holding consultations about cybersecurity issues, TASS news agency reported.

Biden told Putin at the summit that certain critical infrastructure should be “off-limits” to cyberattacks after ransom-seeking cybercriminals briefly triggered the closure of a major U.S. pipeline network, interrupting gasoline deliveries and sparking panic-buying.

In some cases of hacking attacks, the United States has accused those responsible of either working directly for the Russian government or from Russian territory. The Kremlin has denied any state involvement in the attacks.

Putin and Biden also agreed to embark on regular negotiations to try to lay the groundwork for future arms control agreements and risk-reduction measures.

In separate comments on Wednesday, Defence Minister Sergei Shoigu said Moscow has called for measures to increase transparency about the deployment of missiles in Europe.

Shoigu said Putin had proposed measures such as a moratorium on the deployment of intermediate- and short-range missiles in Europe to build mutual trust.

“The situation in Europe is overall explosive, which requires concrete steps to be taken for its de-escalation,” Shoigu said. “We are ready to work towards this.”

Putin has accused NATO of dismissing Russian proposals to reduce tensions and the risk of military incidents.

Russia’s relations with the West are languishing at post-Cold War lows, strained by issues ranging from Moscow’s 2014 annexation of Crimea to the conflict in Syria and allegations of Russian hacking of U.S. elections.