Iranian Foreign Minister Mohammad Javad Zarif has condemned a decision by US President Donald Trump to tighten economic pressure against Tehran, saying Washington once again proved that it deliberately seeks to target ordinary people.

Zarif said in a tweet on Wednesday that Trump's decision was meant to escalate the economic war against Tehran regardless of its consequences.

"It’s admission that US is DELIBERATELY targeting ordinary citizens: #EconomicTerrorism, illegal & inhuman," he said.

Escalating US economic WAR on Iranians, @realDonaldTrump ordered SoT "to substantially increase sanctions against the COUNTRY of Iran!"



It’s admission that US is DELIBERATELY targeting ordinary citizens: #EconomicTerrorism, illegal & inhuman.



ُStop war & terror. #Security4All. — Javad Zarif (@JZarif) September 18, 2019

Earlier in the day, Trump said he had ordered Treasury Secretary Steven Mnuchin to “substantially” increase economic sanctions.

“I have just instructed the Secretary of the Treasury to substantially increase Sanctions on the country of Iran!” Trump tweeted, without providing more details.

The announcement came in the aftermath of attacks on two Saudi Aramco oil facilities on Saturday, which knocked out more than half the kingdom’s production.

While Yemen's Houthi Ansarullah movement has claimed responsibility for the attack, the United States and Saudi Arabia insist that Iran is responsible for the strike.

US Vice President Mike Pence said Tuesday that it “looks like” Iran was responsible but investigations were still ongoing.

US Secretary of State Mike Pompeo, who was headed to Riyadh on Wednesday to discuss the matter with Saudi officials, has also put the blame on Iran, claiming, “Tehran is behind nearly 100 attacks on Saudi Arabia” and that “there is no evidence the attacks came from Yemen.”

US Defense Secretary Mark Esper has said that the US military was preparing a response to the attacks.

Tehran, however, has dismissed the allegation, calling it an attempt by Washington to shift from a failed campaign of “maximum pressure” to one of “maximum lying” and “deceit” against the Islamic Republic.

Zarif said after the attack in tweet that “US & its clients are stuck in Yemen because of illusion that weapon superiority will lead to military victory.”

Speaking to reporters on Wednesday, Zarif said that America's campaign of pressure against Tehran has failed and Washington should rejoin the 2015 nuclear deal if it wants a seat at the negotiating table with Iran.

"The united States has shown by now that it holds no value for any agreements and even its own signature," he said. "Today it decides to invite a group to the White House, tomorrow it calls off the meeting or sanctions the same group."

He also accused Washington and Riyadh of deliberately trying to change the realities on the ground in the region by making false accusations against Iran.

"They are now witnessing a situation where their advanced defense systems can't intercept Yemeni missiles and drones and to hide their shame they level accusations against others," Zarif continued.

Russia to US: Expanding Iran bans destructive, pointless

Meanwhile, Russia also slammed as "destructive" and "pointless" Trump's decision to step up economic pressure against Iran.

Russia's Ministry of Foreign Affairs on Wednesday condemned Trump's announcement to "substantially increase" sanctions on Iran.

The ministry warned that sanctions would solve nothing because Iran would not feel the impact as it has long been under unilateral sanctions by Washington and some of its allies.

The statement added that the sanctions, while unhelpful, were still a better alternative to military solution, which has been touted several time by some American officials.