Several Group of Seven leaders presented a united front on upholding their sanctions against Russia as they opened their annual summit Sunday, making clear that now is not the time for a softer stance.

This year's meeting of the leading industrialized democracies was the second in a row without Russia, which was ejected from what was the G-8 last year over its actions in Ukraine. Even with President Vladimir Putin absent, Russia was prominent in the leaders' minds as they gathered in the Bavarian Alps.

Chancellor Angela Merkel and President Barack Obama agreed during a pre-summit bilateral meeting that the duration of sanctions imposed upon Moscow should be "clearly linked to Russia's full implementation of the Minsk" peace accord agreed in February, the White House said in a statement. Merkel and French President Francois Hollande, another summit participant, were central to drawing up that accord.

The summit was expected to produce a declaration on Ukraine from all the participants.

Merkel said she expects the G-7 leaders to send a "united signal."

In an interview with ZDF television, Merkel stressed however that sanctions are not an end in themselves and they "can be dispensed with when the conditions under which they were introduced are no longer there and the problems are resolved."

She said that "we have a chance if everyone makes an effort — that is to some extent in Russia's hands and of course in Ukraine's."

Heading in to the talks, British Prime Minister David Cameron said he would push for Europe to stand firm with sanctions against Russia even though some countries — especially cash-strapped Greece — were suffering economically because of declining investment and tourists from Russia.

"It has an impact on all countries in terms of putting sanctions on another country," Cameron said. "Britain hasn't let our pre-eminence in financial services get in the way of taking a robust response to Russian-backed aggression and I don't think other countries should either."

European Union President Donald Tusk told reporters that since the Ukraine peace deal agreed in Minsk has not been fully implemented, the only question for the 28-nation EU is whether to make the sanctions against Russia even tougher.

"If anyone wants to start a debate about changing the sanctions regime, the discussion could only be about strengthening them," said Tusk, a former Polish prime minister. The EU participates in the summits of the G-7 — Britain, Canada, France, Germany, Italy, Japan and the U.S.

After Russia annexed the Crimean peninsula from Ukraine last year, the other world powers kicked the country out of the G-8 in an effort to isolate Putin and to signal the West's united opposition to his actions.

The rift has deepened amid subsequent fighting in eastern Ukraine and several rounds of sanctions against Russia.

The U.S. and the European Union have imposed financial restrictions on Russian companies and individuals to pressure Russia into stopping its support for separatist rebels in eastern Ukraine. They and NATO say Russian troops and military equipment have been used on Ukrainian territory — something Russia denies.

Tusk said Russia's possible return to the G-8 would depend on a turn-around in Moscow's foreign policy.

"This is a community of values. And this is why Russia is not among us here today and will not be invited as long as it behaves aggressively toward Ukraine and other countries," he said.

Tusk said one role for the summit would be "to reconfirm the G-7 unity on the sanctions policy."

Protesters, meanwhile, blocked roads as the G-7 leaders arrived in the Bavarian Alps to begin their two-day summit. Journalists were flown by helicopter to the venue to avoid delays on the roads due to the protesters.

Several hundred demonstrators hiked early Sunday from the resort of Garmisch-Partenkirchen to get near the security perimeter around the Schloss Elmau hotel, the secluded summit venue 8 kilometers (5 miles) away.

Some 22,000 police from around Germany were brought in to keep the protesters away from the hotel.

At the security fence, about 200 protesters shouted chants like "Freedom and peace, no more G-7!" and waved signs with slogans like "Politics for people, not markets." On the other side, about 100 police officers with dogs were patrolling the fence to keep the demonstrators out.

Two protesters broke away from the main group at the security fence in an attempt to sneak through the woods and breach the barrier, but they were quickly chased down and turned back by about a dozen police.

The annual summit has drawn repeated protests by those who believe the leaders' decisions favor banks and business interests over those of ordinary people. A planned trans-Atlantic free trade agreement is a major concern.

Tusk went out of his way to acknowledge the protests, saying that their presence demonstrated the democratic values that G-7 nations stand for.

"People can demonstrate and think what they want, can say what they want, and even look like they want," he said. "I'm sorry for this maybe-trivial truth, but from time to time it's important that someone says it so openly."