President Donald Trump, joined by U.S. Ambassador to the UN Nikki Haley, right, speaks during a lunch with the United Nations Security Council in the State Dining Room of the White House in Washington, Jan. 29, 2018.
President Donald Trump, joined by U.S. Ambassador to the UN Nikki Haley, right, speaks during a lunch with the United Nations Security Council in the State Dining Room of the White House in Washington, Jan. 29, 2018.

WHITE HOUSE - U.S. President Donald Trump has ruled out talks with Afghanistan’s Taliban, vowing to ‘finish” them in the wake of a wave of terrorist attacks in Kabul that killed hundreds of people and wounded hundreds more.
Meeting a delegation of United Nations Security Council ambassadors at the White House Monday, Trump said he would raise the issue of “what more we can do to defeat” the insurgent group. 

“There’s no talking to the Taliban,” he said, seemingly putting an end to hopes of a diplomatic solution to Afghanistan’s long-running domestic conflict.
“They’re killing people left and right. Innocent people being killed left and right,” Trump said to the visiting diplomats. “Bombing, killing all over Afghanistan. So we don’t want to talk with the Taliban. There may be a time but it’s going to be a long time.”

WATCH: US-Afghan relations

?Trump last year reversed the Obama-era drawdown of the American presence in Afghanistan, sending additional U.S. troops to the Central Asian nation and ordering increased military assistance to Afghan forces.

Trump did not specify what he has in mind, but suggested that a stronger military response is imminent.

“What nobody else has been able to finish we’re going to be able to do it,“ he said.
Behind closed doors, the president also spoke to the Security Council delegation about ramping up pressure on Tehran in return for staying in the 2015 Iran nuclear deal, which he has described as “horrible.”
Earlier this month, Trump agreed to extend the nuclear deal negotiated to by his predecessor Barack Obama, but said he would terminate it unless Congress and European allies agree to strengthen it by May.

”This is a last chance,” Trump said.  “Either fix the deal’s disastrous flaws, or the United States will withdraw.”
Trump’s ultimatum is part of a larger U.S. strategy of imposing consequences against Tehran for its other negative behavior in the region, including supporting groups like the Houthis and Hezbollah in Lebanon.
Washington’s U.N. Ambassador Nikki Haley accused Tehran in December of hiding behind the nuclear deal, saying “these are the things they are doing while we are all looking the other way.”

FILE - U.S. Ambassador to the U.N. Nikki Haley wal
FILE - U.S. Ambassador to the U.N. Nikki Haley walks in front of allegedly recovered segments of an Iranian rocket during a press briefing at Joint Base Anacostia-Bolling, Dec. 14, 2017, in Washington.

Experts say finding a way to avoid a U.S. pullout from the deal is focusing minds on Capitol Hill and in foreign capitals, as well as in Tehran.
 “If America’s European allies do not work with the United States, President Trump has made it emphatically clear that he is going to walk away from the deal about 100 days from now,” said Nile Gardiner, of the Heritage Foundation in Washington.  “I have no doubt he will walk away from the deal unless it is significantly strengthened.”
Matthew Bey, an analyst at the geopolitical research firm Stratfor in Austin, Texas says it is going to be difficult to find a way to amend the Iran nuclear deal that is satisfactory to all parties, including the government in Tehran. 

“How they are going to figure that out remains to be seen,” he told VOA.
Bey said, however, that there are indications Trump’s threat is being taken seriously.

“The Europeans are interested, and while Iran has publicly denied any interest in negotiating anything, there have been enough leaks and signs to suggest that at least underneath the table, (Foreign Minister) Javad Zarif and the Europeans are talking,” he said.
Bey said a deal might involve a voluntary agreement by Tehran not to conduct long distance ballistic missile tests.  

“I think there’s actually some dialogue going on from the Iranian perspective that leads me to believe there’s ground to be made, and that, despite all the challenges it’s might somehow actually survive,” he said.
The Security Council was shown an exhibit of what have been identified as large pieces of Iranian short-range missiles believed to have been fired at Saudi Arabia’s capital, Riyadh, by Houthi rebels from Yemen.  Haley first showed the missile parts at a December news conference, calling them “undeniable evidence” that Iran was illegally arming the Houthis.

American officials have indicated they plan to hold Iran accountable at the United Nations for violations of an international arms embargo on the Yemeni rebels.