She went on: "You are not my family. You are not my friend", Cattrall continued.
She also included a link to a story by the New York Post in the caption about the "mean-girls culture" the paper claims "destroyed" the HBO series. Cattrall's brother was reported missing last week and was later found dead by Canadian police, less than 24 hours after the report.
The tension between Cattrall and Parker reignited last fall, following reports that Cattrall had sunk production for a third "SATC" movie, which she has repeatedly denied.
Cattrall's brother Chris was reported missing on February 3 and a day later, she took to Instagram to announce his sudden passing.
We send our love and condolences to Kim and her entire family during this painful time.
'True American heroes': Two Ohio officers killed responding to hung-up 911 call
The city of Westerville confirmed on Twitter reports that two of the city's police officers were killed in "the line of duty". Westerville is 15 miles north of downtown Columbus. "These officers were two of the best we had", he said.
Syria war: Last of British IS 'Beatles' gang captured by Kurds
Former hostages describe severe mistreatment, beatings and mock executions at the hands of their jailers, especially the Britons. USA officials said the "execution cell" had beheaded more than 27 Western hostages and tortured many more.
US Prosecutors Charge 36 Suspects in Global Cybercrime Ring
Actual losses-which hit a wide swath of financial institutions, merchants, and private individuals-totaled more than $530 million. Those arrested stand accused of multiple crimes including identity theft, bank fraud, wire fraud and money laundering.
On screen, Cattrall and Parker - along with Kristin Davis and Cynthia Nixon - portrayed best friends navigating their 30s (or, in Cattrall's case, her early 40s) while pursuing careers, romance and an endless parade of brunches in NY.
On a recent appearance on "Watch What Happens Live with Andy Cohen", SJP was asked by her longtime friend Cohen about an interview Cattrall gave Piers Morgan in which Cattrall said the two women were never friends - "just colleagues".
And Sarah Jessica Parker proved worthy of the title as she arrived at the red carpet Divorce event in NY on Thursday.
Kim Cattral, 61, was born 21 August 1956 in Mossley Hill, Liverpool and is an English-Canadian actress.
She added: "I really think she (Parker) could have been nicer".