Saudi Arabia said Sunday it rejected any threats of economic sanctions or political pressure over the case of missing journalist Jamal Khashoggi, adding that it would retaliate accordingly, according to a statement on the official Saudi Press Agency attributed to "an official."
In an escalation of the growing rift between Saudi Arabia and some Western allies, the Kingdom also said that "if any actions are taken [against it], it will respond with greater action."
"It also affirms that the Kingdom's economy plays an influential and vital role in the global economy and the only thing that will impact the kingdom's economy is the global economy," the statement added.
The statement did not specifically mention Khashoggi, who went missing after entering the Saudi Consulate in Istanbul on October 2 to obtain documents for his upcoming marriage to Turkish fiancée Hatice Cengiz.
Khashoggi, a columnist for The Washington Post and Saudi royal insider-turned-critic, hasn't been seen in public since entering the consulate almost two weeks ago.
In the diplomatic fallout over Khashoggi's disappearance, Saudi Arabia is facing growing isolation as firms pull out of a high-profile investment summit due to take place later this month in Riyadh.
Secretary of State Mike Pompeo on Saturday declined to confirm whether US Treasury Secretary Steven Mnuchin would still be attending the Future Investment Initiative conference being hosted by the Saudi Crown Prince -- known as "Davos in the desert" -- later this month.
"I think we need to continue to evaluate the facts and we'll make that decision -- I talked to Secretary Mnuchin about it last night, we'll be taking a look at it through the rest of the week," Pompeo, alongside President Trump, told reporters in the Oval Office on Saturday.
Doubts are also growing over whether British Trade Secretary Liam Fox will attend the Riyadh conference, the BBC reported Sunday citing diplomatic sources.
A spokesman for the UK's international trade department told CNN that Fox's diary was not yet finalized for the week of the conference.
Mounting evidence, but conclusive proof still missing
Turkish authorities believe 15 Saudi men who arrived in Istanbul on October 2 were connected to Khashoggi's disappearance and possible killing. At least some of them appear to have high-level connections in the Saudi government.
On Friday, a source familiar with the ongoing investigation told CNN that Turkish authorities have audio and visual evidence that Khashoggi was killed inside the consulate.
Saudi Arabia firmly denies any involvement in Khashoggi's disappearance and says he left the consulate that afternoon.
Fiancée describes heartbreak over 'lonely patriot'
Khashoggi's fiancée Hatice Cengiz revealed how the couple spent their last hours together, writing that "tyrants eventually pay for their sins," in a New York Times article on Saturday.
Cengiz, a doctoral student at a university in Istanbul, wrote: "If the allegations are true, and Jamal has been murdered by the errand boys of Mohammed bin Salman, he is already a martyr."
Cengiz said in the article that Khashoggi had been "cheerful" on the morning they traveled together to the consulate, and that the couple had made plans for the rest of their day.
"We were going to browse appliances for our new home and meet with our friends and family members over dinner," she wrote. "When we arrived at the consulate, he went right in. He told me to alert the Turkish authorities if I did not hear from him soon."
The heartfelt article, which described how the pair met at a conference in Istanbul in May and bonded over their "shared passion for democracy, human rights and freedom of expression" was published on Khashoggi's birthday, Cengiz said.
"I had planned a party, inviting his closest friends to surround him with the love and warmth that he had missed," she wrote. "We would have been married now."
Cengiz said Khashoggi fled Saudi Arabia with two suitcases for the US "amid a crackdown on intellectuals and activists who criticized Crown Prince Mohammed bin Salman."
But rather than a dissident, he saw himself as a patriot "using his pen for the good of his country," she said.
Cengiz added that she had seen reports President Trump wanted to invite her to the White House. But she said, "If he makes a genuine contribution to the efforts to reveal what happened inside the Saudi consulate in Istanbul that day, I will consider accepting his invitation."
The US President said Friday he had not yet spoken with King Salman of Saudi Arabia -- the father of bin Salman -- in the wake of Khashoggi's reported killing, but that he planned to "pretty soon."