Asserted

resting on a statement or claim unsupported by evidence or proof; alleged:
The asserted value of the property was twice the amount anyone offered.
to state with assurance, confidence, or force; state strongly or positively; affirm; aver:
He asserted his innocence of the crime.
to maintain or defend (claims, rights, etc.).
to state as having existence; affirm; postulate:
to assert a first cause as necessary.
assert oneself, to insist on one’s rights, declare one’s views forcefully, etc.:
The candidate finally asserted himself about property taxes.
Contemporary Examples

My point is that one man was arrested—not every Tea Party member, as Nye asserted.
Democrats Have Maxed Out the Race Card Ron Christie December 16, 2013

According to the transcriber, Kerry “asserted that [Qatar’s prime minister] was preaching to the converted.”
A One-Sided House Hearing Against Palestinian Reconciliation Zaid Jilani February 4, 2013

And third, General Dempsey was right when he asserted that Iran is a rational actor.
Why Obama Won’t Back a Strike on Iran Andrew Bast February 25, 2012

Because, Michelle asserted, presidents can have the wisest advisers in the world.
Michelle Obama’s Iron Fist, Velvet Glove Convention Speech Michelle Cottle September 4, 2012

The former News of the World journalist Paul McMullan asserted openly that his bosses had been well aware of the hacking.
Guardian Journalist Gives Testimony on Hacking Scandal William Underhill November 28, 2011

Historical Examples

It was also asserted that the Commissioners had recognised him as the chaplain of the asylum.
Norfolk Annals Charles Mackie

“I like I should live always by mine own place,” asserted Mrs. Kukor.
The Rich Little Poor Boy Eleanor Gates

It is asserted by all the chroniclers that the influence of the League (Ligue) was most pernicious.
The History of Prostitution William W. Sanger

“He never makes a mistake,” asserted the Bear King, stoutly.
The Lost Princess of Oz L. Frank Baum

By this decision, he asserted a court supremacy over Parliament with respect to the validity of statutes.
Our Legal Heritage, 5th Ed. S. A. Reilly

verb (transitive)
to insist upon (rights, claims, etc)
(may take a clause as object) to state to be true; declare categorically
to put (oneself) forward in an insistent manner
v.

c.1600, “declare,” from Latin assertus, past participle of asserere “claim, maintain, affirm” (see assertion). Related: Asserted; asserting. To assert oneself “stand up for one’s rights” is recorded from 1879.