Russian and Ukrainian delegates concluded their third set of direct talks in Istanbul “about 40 minutes” after they started, the Russian state news agency TASS reported Wednesday, citing a source.

I STANBUL—President Trump’s ultimatum for Russian President Vladimir Putin is showing no signs of bringing Russia and Ukraine any closer to peace. The third round of direct talks between Ukrainian and Russian officials, held Wednesday in Istanbul, yielded few results. The two sides met for less than an hour.

Officials from Russia and Ukraine began a third round of talks in Istanbul, with potential prisoner swaps on the agenda but little expectation of progress on ending the full-scale war that’s in its fourth year.