ISTANBUL — World leaders have condemned the crippling attack on Saudi oil installations last weekend as a blow to the global economy and a threat to regional stability.President Vladimir V. Putin of Russia evidently also saw it as a chance to make a sales pitch, or at least enjoy a joke, at the expense of the West.Mr. Putin spoke at a joint news conference in Ankara with President Recep Tayyip Erdogan of Turkey and President Hassan Rouhani of Iran on Monday after a meeting about the Syrian conflict.American officials have blamed Iran for the attack on Saudi Arabia, Turkey is a major regional rival to the kingdom, and Mr. Putin has sought to expand Russian influence on all three countries, including through weapons sales.“The Quran says that any kind of violence is unacceptable, except for one kind of violence, when you protect your people,” Mr. Putin began.“We are ready to help Saudi Arabia protect their people,” he said, with a somber face, but beginning to bob slightly in his chair. “They need to make clever decisions, as Iran did by buying our S300, as Mr. Erdogan did by deciding to buy the most advanced S400 air defense systems.”“These kinds of systems are capable of defending any kind of infrastructure in Saudi Arabia from any kind of attack,” he added.Mr. Rouhani, seated next to Mr. Putin, laughed visibly. The broadcast on the state-owned Russian television network RT captured the Iranian foreign minister, Mohammad Javad Zarif, chuckling to himself in the audience.