"The fact IS claimed responsibility proves that they [Saudi Arabia] were involved in the brutal attack".
Khamenei said the US and its allies' engagement in the Middle East to fight terrorism is a "lie" and referred to them as "the source of instability in the Middle East".
On Tuesday, Iran's Foreign Minister Mohammad Javad Zarif referred to those remarks by the Saudi officials and called them a "direct threat and very risky provocation" by Riyadh.
He also blasted any attempts at building bridges with the United States, saying: "America is a terrorist country and backs terrorism. therefore, we can not normalise ties with such country".
It comes as relations between Tehran and Washington have grown increasingly strained, most recently overshadowed by a string of allegations made by a number of high-ranking Iranian officials claiming the U.S. had forged an alliance with Islamic State (IS, formerly ISIS/ISIL). Major General Mostafa Izadi, deputy chief of staff of Iran's armed forces, said Sunday that the government in Tehran had "documents and information" showing Washington's support of the extremist Sunni Islamist group.
Following the Ryad Summit which US President Donald Trump attended, Bahrain, Saudi Arabia, Egypt, the United Arab Emirates, Yemen, Libya, the Maldives and Mauritius severed diplomatic relations with Qatar on June 5.
Earlier, Iranian Parliamentary Speaker Ali Larijani accused Washington of being an ally of Islamic State in the region.
The top Iranian diplomat also exchanged views on the Joint Comprehensive Plan of Action (JCPOA) with the High Representative of the European Union for Foreign Affairs and Security Policy Federica Mogherini at Oslo Grand Hotel.
"We are facing a proxy warfare in the region as a new trick by the arrogant powers against the Islamic Republic", Izadi said Sunday according to Iran's semiofficial Fars News Agency.
Last Wednesday, terrorists attacked the Iranian Parliament and the Mausoleum of the late founder of the Islamic Republic, Imam Khomeini, in the capital Tehran, killing as many as 17 people.
The comments sparked an immediate backlash from Iran.
House Oks bill to expand off-track betting
Those provisions imposed higher levels of health insurance coverage for MMA fighters than for boxers, plus a gross receipts tax. House Speaker Joe Aresimowicz (ehr-eh-SIM'-oh-wits) is calling the situation "fluid", saying nothing has been finalized.
Apple pushes Siri to the fore at annual developer conference
Apple has finally unveiled its answer to Amazon's and Google's smart speakers slash digital assistants - and it's called HomePod. So far, the service has limited payments to purchases of products and services from companies and other organizations.
WWDC '17: First look at Apple's new iMac Pro
The new iMac Pro will come to market in December of this year, with a starting price of $4,999 for the 8-Core Intel Xeon model. USA chipmaker AMD on Tuesday unveiled a high performance, power-efficient " Radeon Pro 500 " series graphics for Apple iMac .
Super 30 breaks its records, every student cracks JEE
Almost 2 lakh candidates appeared for the exam which was held in 500 different centres across the country. The journey from seeking primary education to qualifying JEE Advanced was not an easy one for Bhairulal.
South Africa: 10000 Knysna residents evacuated amid fire
On Wednesday, authorities urged residents to capture rain from the storm in containers for flushing toilets and other needs. Massive waves smashed over a promenade in Cape Town's Sea Point and Green Point areas, covering it in a blanket of foam.
In Referendum, 97% Support Making Puerto Rico 51st State
The board recommended, among many measures, to cut US$300 million to $500 million from the Puerto Rican state government budget. Organizers expected 1.5 million to watch Sunday's event, held the same day as the US territory holds a referendum on statehood.
Director: 'Wonder Woman' a 'hero' for all
It's received praise from critics and audiences alike while also proving that DC and Warner Bros can make a good movie. She debuted as the superhero in 2016's Batman v Superman: Dawn of Justice, leaving fans excited to see more.
What happened in Bill Cosby's sexual-assault trial
Constand was direct and polite under cross-examination, even when Agrusa's questioning grew pointed and accusatory. These are inconsistencies worth noting, and worth thinking about. "I wouldn't even worry about it", Cosby said.