President Donald Trump on Tuesday backed Spanish Prime Minister Mariano Rajoy's efforts to deal with the situation in Catalonia, saying that Spain is "a great country" that "should remain united" and adding that the region would be "foolish" not to remain joined with Spain.

"I really think the people of Catalonia would stay with Spain. I think it would be foolish not to," the president said at a joint press conference with Rajoy after their White House meeting.

Five days before the referendum that the independence-minded forces are aiming to hold in Catalonia, this was the matter that took center stage at the press conference after a working luncheon at which the two leaders analyzed bilateral relations and international issues such as the threat posed by North Korea and the situation in Venezuela.

Trump's response was welcomed by the Spanish delegation, which felt that it made quite clear the US president's support for the legal position taken by Madrid.

Until Trump's remarks on Tuesday, the White House had said only that the Oct. 1 referendum was an "internal" Spanish matter, although Defense Secretary James Mattis had expressed support for the Rajoy government last weekend at a meeting with his Spanish counterpart, Maria Dolores de Cospedal.

On Tuesday, Trump praised Spain as a "greatly admired country" and emphasized that the two nations are great friends and close allies.

Trump reiterated his solidarity with Spain in the wake of the terrorist attacks last month in Catalonia and, in that regard, thanked Spain for its participation in the coalition against the Islamic State and for having trained more than 30,000 members of the Iraqi security forces.

Before that reference, Rajoy said that he told Trump of Madrid's intention to increase its commitment to the coalition after the retaking of Mosul with the contribution of a new financial aid package for Iraq's reconstruction.

He also emphasized Spain's experience in the fight against terrorism, although he said that there is still room for improvement in coordinating on cybersecurity and preventing terrorist recruitment and financing.

Regarding North Korea, Trump thanked Rajoy for Spain's decision to expel Pyongyang's envoy to Madrid and joining the US in isolating that regime.

Rajoy emphasized that the challenge posed by North Korea is an "unacceptable violation of international legality" and gave Trump his government's full support for strengthening sanctions on Pyongyang, as approved by the UN Security Council.

Venezuela was another point of agreement between Rajoy and Trump, who praised Spain's efforts on behalf of the Venezuelan people and said he was sure that other European nations will sanction the Nicolas Maduro regime.

Trump said that Venezuelans are enduring poverty, hunger and political disruption under their "oppressive" socialist regime, expressing the hope that Venezuela will restore democracy and free its political prisoners.

Trump also backed fair and reciprocal international trade, congratulated Spanish businessmen for their investments in the US and offered to work together with Rajoy in such areas.

Rajoy, in turn, called his meeting with Trump "very productive" and said that Spain and the US enjoy excellent relations.