Texas Senator Ted Cruz has attempted to defend taking a family trip to Mexico amid a winter storm that left millions in his state without power and water.
Mr Cruz said on Thursday he planned the holiday for his daughters, "wanting to be a good dad", but had returned because it "didn't feel right".
Photos of the Republican lawmaker at an airport on Wednesday fuelled outrage at how he had left Texas during a crisis.
Millions of people in Texas face water shortages, with reservoirs near empty.
Freezing temperatures have caused power blackouts at water treatment facilities and burst water pipes supplying homes, despite attempts by some homeowners to insulate them from the cold using blankets.
About 13 million Texans have been told to boil water that may be contaminated.
Mr Cruz, a high-profile Republican who ran for the US presidency in 2016, has not only drawn criticism for taking the international trip, but also for reportedly leaving his dog, Snowflake, behind.
A New York Magazine reporter tweeted an image early on Thursday that appeared to show the senator's home, with Snowflake visible through the glass of the front door.
Just drove by Ted Cruz’s house in Houston. His lights are off but a neighbor told me the block got its power back last night. Also, Ted appears to have left behind the family poodle. pic.twitter.com/TmLyGQkASy— Michael Hardy (@mkerrhardy) February 18, 2021
The canine was reportedly being cared for by a security guard.
How has Cruz defended his trip?
In a written statement released on Thursday afternoon, Mr Cruz said that with schools closed in the state, he had booked the vacation for his young daughters who "asked to take a trip with friends".
The senator said he and his staff were "in constant communication with state and local leaders to get to the bottom of what happened in Texas".
Mr Cruz did not apologise for making the trip amid the state of emergency in Texas, but in a later interview with broadcaster ABC13, he said it was "a mistake".
"In hindsight, if I had understood how it would be perceived, the reaction people would have, obviously I wouldn't have done it," he said, adding that he had had "second thoughts as soon as we left" and understood why people were "upset".
"Leaving when so many Texans were hurting didn't feel right, and so I changed my return flight and flew back on the first available flight I could take," he said.
The Republican has now returned to Houston.
As a federal lawmaker, Mr Cruz does not have a direct role in Texas' emergency response, but residents often reach out to their elected officials - like Mr Cruz - during natural disasters for help accessing resources.
What's the reaction been?
The senator's travel plans amid the crisis in Texas drew immediate criticism online.
"People in Texas are literally freezing to death and yet Ted Cruz went on vacation to Cancun," wrote Democratic Congresswoman Pramila Jayapal on Twitter.
"Ted Cruz not only fled the state while millions of vulnerable Texans are without heat and water but specifically diverted police resources to get him through security and crowds faster for his outgoing vacation flight," wrote progressive rights activist Charlotte Clymer on Twitter.
Just confirmed @SenTedCruz and his family flew to Cancun tonight for a few days at a resort they've visited before. Cruz seems to believe there isn't much for him to do in Texas for the millions of fellow Texans who remain without electricity/water and are literally freezing. pic.twitter.com/6nPiVWtdxe— David Shuster (@DavidShuster) February 18, 2021
Some criticised Mr Cruz for appearing to use his daughters to deflect blame.
Journalist Leah Binkovitz appeared to mock the senator, writing on Twitter: "I relate to Ted Cruz because my kids have also asked tough questions of me lately like, 'what happens if we run out of food and water'."
The chairman of the Republican Party in Texas, Allen West, said Mr Cruz "has to answer to his constituents" for the decisions he has made during the current winter weather crisis.
But some conservatives came to Mr Cruz's defence - author and activist Brigitte Gabriel wrote: "Senator Ted Cruz is one of the hardest working men in the country, he deserves a vacation."
Mr Cruz's trip to Mexico also raised concerns among other parents whose children attend the same private school in Houston as his daughters.
The school's policy states that students who travel abroad cannot return to classrooms for seven days after returning home, the New York Times reported.
It adds that students must take a coronavirus test within three to five days of returning, which must then produce a negative result before they can return to classrooms.
Others suggested the added scrutiny may hurt Mr Cruz as he reportedly contemplates a second presidential bid in 2024. The lawmaker's current Senate term will expire in early 2025.
What's the situation in Texas?
At least 47 storm-related deaths have been reported and hospitals have been placed under severe pressure.
Food supplies in supermarkets are running low and residents are struggling to keep warm in some of the coldest temperatures the state has seen in more than 30 years - hitting 0F (-18C) earlier this week.
Texas has opted out of the national power grids, and so has been particularly hard hit by the exceptional conditions.
Outages are expected to continue for days.
Governor Greg Abbott has asked residents to shut off water to their home if possible to help keep pressure up amid concerns over the disruption in supply to hospitals.
Mr Cruz had been active on Twitter in recent days, sharing updates about power in the state.
In his Thursday statement, Mr Cruz said that his family had also lost heat and power, just like other Texans.
"The greatest state in the greatest country in the world has been without power," he said.