President Vladimir Putin said Friday he has secured Israel's pledge to safeguard Russian personnel at Iran's Russia-built nuclear power plant and that he has reached out to both sides to try to end the week-old war.

Last week, Israel struck four buildings at the Isfahan nuclear site, among them a uranium conversion facility. The IAEA said there has been no sign of increased radiation at Isfahan, which is roughly 350 kilometers (215 miles) southeast of Tehran.

Russia warned against efforts to force a regime change in Iran and said it would react “very negatively” if Iran’s Supreme Leader Ayatollah Khamenei were killed, raising concerns of a broader escalation in the Israel-Iran conflict as European leaders came together with Iran on Friday for a diplomatic meeting.