ISTANBUL — In his most blatant criticism yet of Syria’s political repression, the prime minister of Turkey said for the first time on Tuesday that President Bashar al-Assad of Syria should resign, raising the pressure on Mr. Assad from a country that Syria had once counted as its friendliest neighbor and economic partner.

The criticism by the Turkish prime minister, Recep Tayyip Erdogan, of Mr. Assad was not totally unexpected, given Mr. Erdogan’s increasing exasperation with Mr. Assad’s intransigence over the political uprising against him, now in its eighth month. But Mr. Erdogan’s comments were notable for his explicit language. He likened Mr. Assad to the self-delusional dictators of history who met violent ends, most recently Col. Muammar el-Qaddafi of Libya.

“Just remove yourself from that seat before shedding more blood, before torturing more and for the welfare of your country, as well as the region,” Mr. Erdogan said of Mr. Assad in a televised statement at his party meeting in Ankara, the capital.

“It is not heroism to fight against your own people,” Mr. Erdogan said. “If you want to see someone who has fought against his own people, look at Nazi Germany, Hitler, Mussolini, Ceausescu of Romania. If you do not learn your lesson from them, look at the Libyan leader, who pointed his gun against his own people and, only 32 days ago, got killed in a way that none of us desired, after using the same phrases that you use.”