SINGAPORE — Secretary of State Mike Pompeo urged Turkey to release an imprisoned American pastor whose case has been a sore point between Ankara and Washington, and acknowledged that it will take a long time to achieve the denuclearization of North Korea.

Speaking to reporters aboard his plane en route to Singapore from Malaysia, Pompeo said he planned to raise the detention of the pastor, Andrew Brunson, and others jailed in Turkey when he met with Foreign Minister Mevlut Cavusoglu on the sidelines of a conference of 27 Asian nations.

Pompeo’s three-day trip to Asia, including a stop at the ministerial meeting in Singapore of the Association of Southeast Asian Nations (ASEAN), is part of a U.S. effort to boost trade ties with the region, despite withdrawing from the Trans-Pacific Partnership free-trade agreement.

In bilateral meetings, Pompeo also pressed for continued sanctions enforcement against North Korea.

Pompeo met with Cavusoglu immediately after arriving from Malaysia. A State Department description of their conversation said only that they addressed a number of issues during a “constructive” conversation.

The State Department has demanded that Turkey release several American detainees, including Brunson, who has been detained almost two years, and Serkan Golge, a Turkish American NASA scientist, as well as three locally hired employees of U.S. diplomatic missions in Turkey. All were taken into custody in a crackdown after a failed military coup attempt in 2016. Last week, Washington imposed sanctions on Turkey’s interior and justice ministers over Brunson’s jailing.

“Brunson needs to come home,” Pompeo said he would tell Cavusoglu. “As do all the Americans that are being held by the Turkish government. It’s pretty straightforward. They’ve been holding these folks for a long time.

“These are innocent people,” he added. “Pastor Brunson is an innocent pastor, and they need to let him return to the United States, and they need to let our locally employed folks — everyone needs to be let out. That’s the message. We are going to work to see if we can find a way forward — I am hopeful.”

Pompeo said the Turkish government is aware that U.S. patience with Turkey over the Brunson case is growing thin.

“The Turks were well on notice that the clock had run and that it was time for Pastor Brunson to be returned,” he said. “And I hope they’ll see this for what it is, a demonstration that we’re very serious. We consider this one of the many issues that we have with the Turks.”

After their meeting, Cavusoglu told Turkish television that he had reiterated Turkey’s message that “threatening language and sanctions does not achieve anything,” but he still described the meeting as “constructive.”

In his remarks to reporters on board the plane, Pompeo also acknowledged the large amount of work that lies ahead before an agreement can be reached to denuclearize North Korea. Although he has made similar predictions before, he sounded particularly blunt. Recent reports suggest that North Korea may be building new missiles.

“Chairman Kim made a commitment to denuclearize,” Pompeo said of North Korean leader Kim Jong Un. “The world demanded that he do so in the U.N. Security Council resolutions. To the extent they are behaving in a manner inconsistent with that, they are in violation of one or both the U.N. Security Council resolutions. . . . We still have a ways to go to achieve the ultimate outcome we’re looking for.”

North Korean Foreign Minister Ri Yong Ho is in Singapore at the same time as Pompeo, leading to speculation the two may meet to discuss the stalled negotiations.

While Pompeo was holding his meetings, Iran’s top diplomat also was in town meeting with fellow diplomats days before the United States reimposes the first nuclear-related sanctions that were lifted under the 2015 deal and ordered slapped back when President Trump withdrew from the agreement this year.

Foreign Minister Mohammad Javad Zarif tweeted that he had been meeting with his counterparts from around Asia, as well as Russia, at ASEAN.

“Clear global consensus on need to take concerted action to preserve JCPOA,” Zarif tweeted, using an acronym for the pact’s official name, the Joint Comprehensive Plan of Action.

State Department officials have said Pompeo will not engage with Iran at ASEAN.

Pompeo’s trip began with a meeting Friday with Malaysia’s newly elected leader, as he sought to promote U.S.-style development led by private-sector investment at a time when the Malaysian government is reconsidering Chinese-financed projects favored by the previous ruling coalition.

In a speech in Washington on Monday, Pompeo reiterated an argument often made by Rex Tillerson, his predecessor, that China offers countries a poor deal because it primarily provides loans, while the United States gives a more sustainable alternative through direct aid and private investment.

Pompeo was the first senior U.S. official to visit Malaysia since surprise election results in May brought an opposition government to power pledging to tackle corruption. The election ended decades of rule by the National Front coalition, in what has been heralded as one of the few and unexpected democratic victories in Southeast Asia.

Pompeo met with Prime Minister Mahathir Mohamad, a 93-year-old fiery politician who once again is leading Malaysia after a 22-year tenure at its helm from 1981 to 2003.

Mahathir led the opposition coalition that now governs Malaysia, partnering with politicians who were locked up under the government he had led previously. He ousted Najib Razak, once his protege, who Mahathir said had become corrupt and maintained an unchecked hold on power. Najib is under investigation in connection with the disappearance of billions of dollars from the state investment fund.

Before his trip, Pompeo announced $113 million in direct government investment to the Asia-Pacific region focused on technology, energy and infrastructure. It is an answer to China’s Belt and Road Initiative, which has provided billions in funding for infrastructure and other big-ticket projects throughout the region.

Under Malaysia’s former government, China signed agreements for several infrastructure projects, including a rail line and pipeline. Several of these Chinese-backed projects — $23 billion worth — have been suspended, as Mahathir’s government questions their value and tries to tackle Malaysia’s fiscal woes related to the corruption scandal.