Qatar on Wednesday promised to make a $15 billion direct investment in Turkey, badly hit by a currency crisis amid a widening diplomatic standoff with the United States, officials said.
"Qatar has pledged $15 billion of direct investments in Turkey," presidential spokesman Ibrahim Kalin wrote on Twitter.
"Turkish-Qatari relations are based on solid foundations of true friendship and solidarity," he said.
The announcement came after Qatar's emir Sheikh Tamim bin Hamad Al-Thani held lunchtime talks with Turkish President Recep Tayyip Erdogan.
A presidential source also confirmed Doha's pledge to "rapidly implement the $15 billion investment package."
Turkish Finance Minister Berat Albayrak, who is Erdogan's son-in-law, and his Qatari counterpart Ali Sharif Al-Emadi were present at the talks in the capital Ankara.
Turkey and Qatar, a very close US ally, have become close economic and political partners in recent times.
Turkey has been rocked in recent days by a sharp decline in the value of its lira after US President Donald Trump tweeted last Friday that Washington was doubling aluminium and steel tariffs for Ankara.
Washington's move came during an ongoing dispute over Turkey's holding of an American pastor for two years.
In response, Erdogan has called for a boycott of US electrical goods while Ankara has sharply hiked tariffs on some US goods.