United States President Donald J. Trump tweeted his support for the U.S.-led joint bid for the 2026 World Cup on Thursday night, but cautioned it would be a "shame" if the U.S.'s allies lobbied against it.

The tweet from Trump comes with the FIFA Congress set to vote on the hosting rights on June 13 in Moscow. Morocco is the only other country competing against the North American bid, which includes Mexico and Canada.

It read: "The U.S. has put together a STRONG bid w/ Canada & Mexico for the 2026 World Cup. It would be a shame if countries that we always support were to lobby against the U.S. bid. Why should we be supporting these countries when they don't support us (including at the United Nations)?"

Mexico president Enrique Pena Nieto replied to Trump's tweet shortly afterward, writing: "We can have differences but soccer unites us. Together we support the bid of Mexico, Canada and the USA to host the 2026 World Cup. @realDonaldTrump @JustinTrudeau."

ESPN reported in February the race between the joint bid and Morocco was already much closer than expected, despite the fact that the North American proposal has the required infrastructure already in place. This is due in part to the policies of Trump, including a travel ban against mostly Arab countries. Lingering resentment over the U.S. Department of Justice investigation into FIFA corruption has also hampered the U.S.-led bid's effort to attract votes.

The U.S. has put together a STRONG bid w/ Canada & Mexico for the 2026 World Cup. It would be a shame if countries that we always support were to lobby against the U.S. bid. Why should we be supporting these countries when they don't support us (including at the United Nations)? — Donald J. Trump (@realDonaldTrump) April 26, 2018

The ensuing months have seen several European countries -- including Russia, France and Belgium -- announce their support for Morocco's bid, which is also likely to earn significant support from African nations, which total 56 votes.

There are also questions about the level of support for the U.S.-led bid in the Caribbean, with the governments of St. Lucia and Dominica announcing their support for Morocco, though Caribbean Football Union president Randolph Harris cautioned it did not reflect how their respective football associations would vote.

The North American bid has secured an endorsement from CONMEBOL and its 10 countries, as well as the six Central American countries absent Guatemala, which is suspended. Saudi Arabia has also announced its support for the joint bid.

A statement from a United Bid spokesperson read: "From the beginning, we have received strong support from the Canadian, Mexican and United States governments. We are grateful for that support and together our three countries are ready to welcome players and fans from around the world to an extraordinary FIFA World Cup in 2026."

FIFA recently completed a technical tour of the countries involved in both bids, with the governing body engaging in a follow-up visit to Morocco after it found deficiencies in the bid related to stadiums.

Morocco plans to invest upward of $16 billion on infrastructure, which includes building or renovating all 14 stadiums.

There were also concerns that Morocco did not declare its anti-LGBT law to FIFA in the human rights risk assessment included in the bid book.