Two dogs covered in melted black tar were rescued off a roof on one of the hottest days of the year during a heat wave in New Jersey, United States.

On July 22, an animal shelter received a call that two dogs were in extreme distress on a roof and the Newark-based Associated Humane Popcorn Park Shelter went to investigate.

The group was confronted with the horrific sight of a Pit Bull and a Yorkshire Terrier 'frantically "dancing" on the roof in an attempt to stop their feet from burning.'

Temperatures had reached 96 degrees and the group wrote on its Facebook page that the tar on the roof was 'bubbling, boiling, and burning these helpless dogs.'

The Yorkie was continually running to the edge of the roof to try and find a place that wouldn't burn her feet, while the pit bull had 'nearly given up hope,' wrote the group.

While the dogs had some food, the group says 'there wasn't a drop of water in sight.' The roof was also covered with feces. 

Rescuers said it looked like the dogs had been there for quite some time. No one was in the apartment below.

After rescuers removed the distraught dogs, they were rushed to an animal hospital.

'How can people be so incredibly cruel? At Associated Humane Societies, we ask ourselves this question every day. But in some cases, there are just no words to describe the feelings we have when we encounter situations like this one,' the group wrote on Facebook.

The dogs are now resting comfortably and not in pain and are being treated for extensive burns and injuries. The group says the dogs' condition is guarded but it has high hopes for their recovery.

The Humane Society said that it received a message from someone claiming to own the Yorkie who said that she was out of town and had given the pooch to someone else to watch, according to NBC New York.

But the group also said it had not been able to get in touch with the person since. 

As for criminal charges against the owner or owners, the shelter wrote on Facebook: 'If you look at just these two pictures of the pit bull with a burned face, covered in hot tar, and the rear end of the Yorkie burned and caked in tar, it's very obvious that this is outright animal cruelty, abuse and neglect.'

It added that animal law enforcement agencies in Newark will be investigating.

'Hopefully, these poor dogs will get the justice they deserve,' the group said.

The shelter is asking for donations to help cover the costs of the dogs' medical treatment.

The group made a plea for people to watch out for animals, especially in this extreme heat.

'These two dogs are alive today because someone saw them and decided to make a call instead of ignoring the situation and figuring someone else will deal with it. Animals cannot speak for themselves. Please get involved,' it wrote.