Trump, who doubled steel and aluminum tariffs on Turkey, said the steel tariffs have kicked in the aluminum tariffs will take effect soon.
The United States and Turkey have exchanged tit-for-tat tariffs in an escalating attempt by Mr Trump to induce Turkish president Tayyip Erdogan into giving up Mr Brunson, who denies charges that he was involved in a coup attempt against Mr Erdogan two years ago.
Trump prefaced Mnuchin's remarks by saying that Turkey had not been a very good friend.
Finance Minister Berat Albayrak assured worldwide investors on Thursday that Turkey would emerge stronger from its currency crisis, insisting its banks were healthy and signalling it could ride out the dispute with the United States. The two countries already disagree over US support for Kurdish fighters in Syria, as well as a plan by Turkey to buy Russian missiles.
Treasury Secretary Steve Mnuchin said during a cabinet meeting Thursday that the U.S.is prepared to levy more economic sanctions against Turkey if Brunson is not released. Turkey, for its part, hiked tariffs on some United States goods such as tobacco, alcohol, cars, cosmetics and launched a boycott of USA electronic devices, including Apple iPhones.
Turkey has taken advantage of the United States for many years. "It is a shame", Erdogan said in a speech on Saturday.
"Do you think the lira will gain against the dollar if Brunson is released?" Kemal Kilicdaroglu, head of the Republican People's Party, said Thursday in Ankara, the capital.
Trump said the United States had helped Turkey in a related incident, but that the North Atlantic Treaty Organisation ally had not repaid the favour.
Supporters of Brunson, who ran a small church in the Turkish coastal city of Izmir, say allegations that he was linked to Kurdish rebels as well as Turkish cleric and alleged coup plotter Fethullah Gulen are absurd.
Turkish President Recep Tayyip Erdogan has bristled at such US pressure. Trump tweeted on Thursday. He was recently moved from prison to house arrest. He criticized Turkey for "holding our wonderful Christian Pastor".
"A one-dollar American bill was found in Dr. Golge's possession when arrested".
The 50-year-old pastor and the USA government vehemently deny those charges.
American officials have also protested the detentions of several Turkish employees of the US diplomatic mission in Turkey, including Metin Topuz, Hamza Ulucay and Mete Canturk.
Turkey has sought to persuade the United States to spare Turkey's state-owned Halkbank from a threatened fine for allegedly helping Iran evade USA sanctions. Brunson faces up to 35 years in Turkish jail over a number of charges, which include espionage and acting "on behalf of terror groups".