joining us now for more is nbc's chief foreign correspondent, richard engel. richard, i didn't expect to have you back on the show so soon after talking with you last night on a totally different matter. thanks for joining us on short notice tonight to help us through this. >> reporter: not a problem. and i was speaking a short while ago with a senior u.s. official with direct knowledge of this. this was a message to iran and iranian-backed militias, according to this official. and the message was that the united states will no longer tolerate harassment, will no longer tolerate attacks, rocket attacks, missile attacks, and particularly, the attack on erbil earlier this month was seen as something of a watershed moment. so, this was a message that times have changed, that even though president biden wants to negotiate with iran, this administration does not want to be bullied, does not want to be pushed around, and is not going to accept increased military action that put u.s. personnel and allies at risk. so, this was a strong message. it was described to me

richard joins us live here next. t and richard engel. richard joins us live here next. they have businesses to grow customers to care for lives to get home to they use stamps.com print discounted postage for any letter any package any time right from your computer all the services of the post office plus ups only cheaper get our special tv offer a 4-week trial plus postage and a digital scale go to stamps.com/tv and never go to the post office again. >>> joining us now is nbc news chief foreign correspondent richard engel who along with the investigative group bellingcat broke the story tonight that one of the women arrested for the capitol attack, in her case for helping to steal, allegedly, nancy pelosi's laptop out of her office, is the same woman seen in this video saying hitler was right, espousing nazi ideology and giving a heil hitler nazi salute. richard, thank you for making time to be here tonight. i will tell you, i feel like you have definitely already robbed me of at least one night's sleep. i find this to be incredibly unnerving stuff. >> reporter: it is a

engel, congratulations on this, richard. and thanks for making time to help us understand it tonight. it is deeply unsettling and deeply important stuff. it's good tasee you my friend. >> sorry if i'm going to leave that image in your mind for the night, but aside from that we'll also be watching khashoggi tomorrow. fascinating stuff. >> indeed. thank you, my friend. we'll be right back. stay with us. stay with us tide pods ultra oxi one ups the cleaning power of liquid. can it one up spaghetti night? it sure can. really? can it one up breakfast in bed? yeah, for sure. thanks, boys. what about that? uhh, yep! it can? yeah, even that! i would very much like to see that. me too. tide pods ultra oxi. one up the toughest stains with 50% more cleaning power than liquid detergent. any further questions? uh uh! nope! one up the power of liquid with tide pods ultra oxi. so you want to make the best burger ever? then make it! that means selling everything. and eating nothing but cheese till you find the perfect slice... even if every

engel, congratulations on this, richard. and thanks for making time to help us understand it tonight. it is deeply unsettling and deeply important stuff. >> sorry if i'm going to leave that image in your mind for the night, but aside from that we'll also be watching khashoggi tomorrow. vasinating stuff. >> indeed. thank you, my friend. we'll be right back. stay with us. k you, my friend we'll be right back. stay with us it works naturally with the water in your body to unblock your gut. free your gut, and your mood will follow. fine, no one leaves the table until your finished. fine, we'll sleep here. ♪♪ it's the easiest because it's the cheesiest. kraft. for the win win. it only takes a second for an everyday item to become dangerous. tide pods child-guard pack helps keep your laundry pacs in a safe place and your child safer. to close, twist until it clicks. tide pods child-guard packaging. i'm susan and i'm 52 and i live in san francisco, california. i have been a sales and sales management professional my whole caree

richard engel is our nbc chief foreign correspondent and the host of "on assignment." this special hour on covid mutations airs sunday, 10:00 p.m. eastern. don't miss it. i'm not going to. richard, we appreciate you making time tonight. hope you get a little sleep before the sun comes up, my friend. >> my pleasure. >>> coming up next, a story that both rachel and i are very geekily excited about. stay with us. i'm super emma. but when we realized she was battling sensitive skin, we switched to tide plus downy free. it's gentle on her skin, and out cleans our old bargain detergent. so, she can focus on saving the world, with a little help from dad. tide pods plus downy free. safe for sensitive skin with eczema and psoriasis. wanna build a gaming business that breaks the internet? that means working night and day... ...and delegating to an experienced live bookkeeper for peace of mind. your books are all set. so you can finally give john some attention. trusted experts. guaranteed accurate books. intuit quickbooks live. when you've got a business, you don't want to worry

. >> that was my nbc news colleague, richard engel, host of on assignment. breaking down in layman's terms, how the virus mutation slipped by the immune system. the cdc warns that these new variants spread more easily and quickly, which could lead to more cases of the virus, which would, in turn, put even more strain on the health-care system. leading to more hospitalizations, and potentially, more deaths. now, there is some hopeful news about our current vaccines. the so-called mrna vaccines, providing protection against these mutations. there is also research showing them to have reduced effectiveness, when compared to the original strain of the virus. but, don't despair. >> but hope is not lost. science may come to our rescue. the new type of mrna vaccines, developed by pfizer, moderna, and others, are so revolutionary, they can be quickly reprogrammed to adapt, as viruses mutate. >> just a modern way of making -- making vaccines. which gave us, also, the ability to respond with an effective and safe vaccine. >> reporter: invented the pfizer vaccine. he i