On May 7, a day before the president Donald Trump announced that the US would withdraw from the Iran nuclear deal, a former US ambassador to Russia gave a prescient warning, telling Quartz that the withdrawal would play straight into president Vladimir Putin’s hands.

And that’s what’s happened. ”Russia is ready to invest $50 billion in Iran’s oil and gas sectors,” Akbar Velayati, a senior adviser to Iran’s supreme leader, told the Financial Times (paywall) on Friday. “Military and technical co-operation with Russia is of major importance to Iran.”

It’s one of the biggest steps the two countries have taken to counter the threat of US sanctions. Before the US withdrawal from the nuclear deal, there was little, if any, energy or economic co-operation between the two countries, according to the FT.

The investment decision was confirmed by a Russian official. And it follows from an earlier announcement Putin made on his visit to Tehran, signing an agreement to invest up to $30 billion (paywall) in Iran’s energy sector.

Velayati also told reporters that a Russian oil company (without naming it) has already signed a $4 billion deal. When details are made public, it will become the second such deal confirmed, following Russian oil company Zarubezhneft’s $740 million investment the Aban and West Paydar oilfields.

Trump is due to meet Putin on Monday (July 16) in Helsinki. He was expected to demand Putin to curb Iranian influence in Syria and threaten further sanctions if Russian companies continued doing business with Iran.

But it seems that, beyond energy investments, Russia and Iran are also co-operating more strongly on their presence in Syria. “Iranians and Russians will [continue to] stay in Syria to ensure terrorists can no longer be active in that country,” Velayati told reporters. “Iran’s presence in Syria has nothing to do with Israel.”

About the same time as Velayati was meeting Putin, the US Department of Justice indicted 12 Russians for hacking the 2016 US presidential elections. The announcement follows Trump’s disruptive NATO summit, where senior diplomats said the US president had done damage to the Western alliance, and his protest-filled visit to the UK, where British officials did their level best to keep protesters out of Trump’s view.

The list of questions Trump must ask Putin keeps growing.