The Latest: Trump says Tuesday special election a 'big race'

The Latest on President Donald Trump's campaign rally in Pennsylvania (all times local):

7:45 p.m.

President Donald Trump is telling rallygoers in Pennsylvania that "we have a big race tomorrow" as he campaigns for a Republican candidate seeking to fill an open congressional seat.

President Donald Trump gestures during a campaign rally in Montoursville, Pa., Monday, May 20, 2019. (AP PhotoMatt Rourke)

Trump campaigned Monday in Montoursville (mahn-TOORZ'-vihl) on behalf of Republican Fred Keller, who faces Democrat Marc Friedenberg in a Tuesday special election.

Trump describes Keller as a "great gentleman, a very successful businessman." He also stresses that Keller "is not letting anything happen to your Second Amendment."

Keller sought to assure Trump about his prospects in Pennsylvania in 2020, saying, "In 2016, Pennsylvania put Donald Trump over the top, and in 2020, we're going to do it again."

President Donald Trump accompanied by Rep. Fred Keller, R-Snyder, arrives at a campaign rally in Montoursville, Pa., Monday, May 20, 2019. (AP PhotoMatt Rourke)

Republicans are attempting to recapture the House seat left open when Republican Rep. Tom Marino resigned in January.

6:20 p.m.

President Donald Trump is heading to Pennsylvania to campaign for a Republican congressional candidate — and himself.

President Donald Trump arrives to speak to a campaign rally, Monday, May 20, 2019, in Montoursville, Pa. (AP PhotoEvan Vucci)

Trump's appearance Monday in the key battleground state comes two days after 2020 Democratic presidential candidate Joe Biden held a campaign rally in Philadelphia.

The president is traveling to Montoursville (mahn-TOORZ'-vihl) on behalf of Republican Fred Keller, who faces Democrat Marc Friedenberg in Tuesday's election to fill the U.S. House seat formerly held by Republican Rep. Tom Marino, who resigned in January. Voters in the heavily GOP district overwhelmingly backed Trump over Democrat Hillary Clinton in the 2016 presidential election.

Trump narrowly defeated Clinton in Pennsylvania in 2016.

Supporters of President Donald Trump cheer as he speaks during a campaign rally, Monday, May 20, 2019, in Montoursville, Pa. (AP PhotoEvan Vucci)

Biden, the former vice president and Pennsylvania native who leads his Democratic presidential rivals, is mounting a strong push in the state.

President Donald Trump speaks during a campaign rally, Monday, May 20, 2019, in Montoursville, Pa. (AP PhotoEvan Vucci)

President Donald Trump speaks during a campaign rally, Monday, May 20, 2019, in Montoursville, Pa. (AP PhotoEvan Vucci)

President Donald Trump speaks during a campaign rally, Monday, May 20, 2019, in Montoursville, Pa. (AP PhotoEvan Vucci)

President Donald Trump arrives to speak to a campaign rally, Monday, May 20, 2019, in Montoursville, Pa. (AP PhotoEvan Vucci)

President Donald Trump speaks during a campaign rally, Monday, May 20, 2019, in Montoursville, Pa. (AP PhotoEvan Vucci)

President Donald Trump speaks during a campaign rally, Monday, May 20, 2019, in Montoursville, Pa. (AP PhotoEvan Vucci)

WASHINGTON (AP) — Russia has moved some troops onto an airbase in Niger where a small number of U.S. forces remain, but Defense Secretary Lloyd Austin said he doesn't see it as a significant issue. Most American troops left that base in the nation's capital, Niamey, a U.S. official said.

The arrival of Russian trainers in the West African country about three weeks ago came in the wake of Niger’s decision to order out all U.S. troops. The order dealt a blow to U.S. military operations in the Sahel, a vast region south of the Sahara desert where groups linked to al-Qaida and the Islamic State group operate.

The Pentagon has said the U.S. troops will depart but has not provided a timeline.

When Russian troops arrived last month, it was unclear where they were staying. The Niamey base, Austin said late Thursday, is located at the capital city's Diori Hamani International Airport, and “the Russians are in a separate compound and don’t have access to U.S. forces or access to our equipment.”

He said the U.S. will continue to watch the situation but he doesn't see it as a significant force protection issue.

A U.S. official said the Russian forces are on the other side of the Niamey facility, known as Airbase 101, and that other international forces — such as the Germans and Italians — also reside. The official spoke on the condition of anonymity to discuss troop movements. It's unclear how many U.S. troops remain at the Niamey base.

The Russian presence on the base comes as tensions remain high between Washington and Moscow over the ongoing U.S. support for Ukraine's military.

About 1,000 U.S. troops are still in Niger, but the bulk of them moved to what's called Airbase 201 near Agadez, some 920 kilometers (550 miles) away from the capital, not long after mutinous soldiers ousted the country’s democratically elected president last July.

A few months later, the ruling junta asked French forces to leave and turned to the Russian mercenary group Wagner for security assistance.

In October, Washington officially designated the military takeover as a coup, which triggered U.S. laws restricting the military support and aid that it can provide to Niger. Since then, diplomatic efforts to restore ties with Niger have been unsuccessful.

Until recently, Washington considered Niger a key partner and ally in a region swept by coups in recent years, investing millions of dollars in the Agadez base, which has been critical to U.S. counterterrorism operations in the Sahel. The U.S. also has invested hundreds of millions of dollars in training Niger’s military since it began operations there in 2013.

The Pentagon also has said the U.S. will relocate most of the approximately 100 forces it has deployed in neighboring Chad for now. Chad is also considering whether to continue its security agreement with the U.S.

Maj. Gen. Pat Ryder, Pentagon press secretary, told reporters that the departure from Chad "is a temporary step as part of the ongoing review of our security cooperation, which will resume after Chad’s May 6th presidential election.”

FILE - Supporters of Niger's ruling junta gather for a protest called to fight for the country's freedom and push back against foreign interference, in Niamey, Niger, Aug. 3, 2023. Russia has moved some troops onto an airbase in Niger where a small number of U.S. forces remain after most American troops left the base in Niamey, the nation's capital, a U.S. official said Thursday, May 2, 2024. (AP Photo/Sam Mednick, File)