MILL CREEK — The City Council intends to fire the city manager here but won’t say why. City Manager Ken Armstrong says he doesn’t know, either.

The council put Armstrong on paid leave Tuesday. It intends to fire him at the end of December.

The vote was unanimous, with all seven council members present, according to a news release issued by the city on Wednesday.

The resolution that removes Armstrong from the city’s top job states that the city attorney will draft a separation agreement.

Armstrong was placed on paid leave through Dec. 30 after a two-hour executive session Tuesday to discuss his job performance. The council then voted in public session. Finance Director Landy Manuel was appointed acting city manager. Until the end of the year, Armstrong will draw a $144,200-a-year salary.

In an interview late Wednesday, Armstrong said the council did not give him a reason for the firing or raise any concerns about his job performance.

“It was a very one-sided process,” Armstrong said. “I was hurt by the lack of communication.”

Mayor Pam Pruitt would not discuss the council’s decision, citing consideration of Armstrong’s privacy. She said she does not expect Armstrong’s departure to affect city budgeting. A public hearing on Mill Creek’s two-year budget is scheduled for 6 p.m. on Tuesday.

Armstrong said he has had some disagreements with the mayor and City Councilman Mark Harmsworth, who resigned Tuesday evening, effective Dec. 31. Harmsworth is on his way to the state House of Representatives.

Armstrong speculates that friction related to things he has written for publications and planning for the city’s biennial budget may have played roles in his firing.

Harmsworth said he could not comment on the circumstances that led to Armstrong’s firing due to privacy concerns. He was the head of a committee that interviewed city staff and council members about Armstrong’s job performance, but Wednesday he declined to share the results.

City Councilman Mike Todd also declined to comment on Armstrong’s termination except to say he felt it was a “tough day” for Mill Creek. City Councilwoman Donna Michelson echoed that sentiment.

“I’m personally very sorry the relationship between the city and Mr. Armstrong didn’t work out,” she said.

Armstrong started as city manager in December 2012. He previously worked for Seattle Public Utilities and served in the U.S. Coast Guard.

Before the city manager can be terminated, state law requires the council to give Armstrong at least 30 days to request a public hearing. If he asks for a hearing, the council will have to take further action to remove him from the job.

Otherwise, Armstrong’s termination is effective Dec. 30. He said he has not decided whether he will request a hearing.

Armstrong’s employment contract calls for severance pay. He will get three months of salary, minus his time on paid leave.

As acting city manager, Manuel will be paid a 10 percent premium on his $116,556-a-year salary until a new city manager is named.

Amy Nile: 425-339-3192; anile@heraldnet.com. Twitter: @AmyNileReports.