Germany began its campaign to add the 2016 European Championship to its 2014 World Cup with a promising 2-0 victory over Ukraine on Sunday, while England and Russia were threatened with expulsion from the tournament.

Shkodran Mustafi's header set Germany on its way to a win that was sealed by substitute Bastian Schweinsteiger in the second minute of injury time, just two minutes after the midfielder had come on to the pitch.

The day's earlier matches both ended in 1-0 victories, with a wonder strike from Luka Modric seeing Croatia past Turkey in a bruising encounter and Arkadiusz Milik scoring for Poland against Northern Ireland.

The football followed a blunt warning from UEFA to England and Russia that their presence at Euro 2016 could be short-lived if their violent fans continued to cause havoc.

Expressing its "utter disgust" over three days of disorder in Marseille, European soccer's ruling body said it warned both football associations that "it will not hesitate to impose additional sanctions ... including the potential disqualification of their respective teams from the tournament, should such violence occur again."

UEFA urged the two associations "to appeal to their supporters to behave in a responsible and respectful manner" at the tournament.

Worryingly, the two sets of fans could again cross paths in Lille this week. Russia next plays Slovakia in Lille on Wednesday afternoon. The following day, England meets Wales 30 kilometers (20 miles) away in Lens.

Authorities in northern France are already bracing for trouble.

If the hooligans have marred the start of the tournament, Schweinsteiger's strike after a lightening counterattack and Modric's stunning volley provided a welcome reminder of what has brought up to 2 million soccer fans to France.

Germany surged forward on the break and Mesut Ozil provided the perfect cross from the left flank for his teammate to hammer into the net.

"A Bastian Schweinsteiger is worth his weight in gold," Germany coach Joachim Loew said.

Schweinsteiger, who suffered his second serious knee injury of the year in training on March 22 and hadn't played since, could barely believe the way his luck had turned.

"Incredible that something like this can happen, you can only wish for it," he said.

There were similar feelings for Modric after he met a high clearance with a 25-meter shot that beat Volkan Babacan in the Turkey goal.

The Real Madrid midfielder wasn't aware that a Croatia fan had breached the stadium security and got onto the pitch to celebrate with the players.

"After scoring this kind of goal I didn't even notice at first," Modric said of the incident. "If he went on the pitch, he went with a really positive attitude."

Poland fully deserved its victory over a Northern Ireland side that looked out of its depth on the big stage.

With Poland forward Robert Lewandowski, qualifying's top scorer, marked out of large stretches of the game, there was space for others to make an impact. One was attacking midfielder Milik, who scored the decisive goal with a low shot in the 51st minute.

Poland could have easily scored more were it not for some erratic shooting.

Their players might learn something from Zlatan Ibrahimovic, whose Sweden side plays Ireland on what should be a great day of football on Monday.

Spain, which is bidding for a third consecutive European crown, takes on the Czech Republic in their opening match, while the action ends with a promising Belgium side facing Italy.