HELSINKI: If Russia and the United States were able to agree on ways of solving the Syrian crisis, this might help towards the two powers finding common ground on Ukraine, Finnish President Sauli Niinisto said on Monday.

The United States and its NATO allies denounced Russia for violating Turkey's air space along its border with Syria on Monday and Ankara threatened to respond if provoked again, raising the prospect of direct confrontation between the Cold War enemies.

In an interview with Reuters, Niinisto said the international crisis over Syria could swing either way.

"There are huge differences in views between Russia and the United States on how to achieve (an end of the Syrian war). We are in a situation where both good and very bad outcomes are possible," he said.

And he said reports of Russian violations of Turkish air space were "not encouraging".

But he added: "If Russia and United States can find something common in Syria, that would reflect on (a solution in) Ukraine.

"We have already seen a surprisingly positive development in Ukraine," he said referring to a suspension of hostilities between Ukrainian government forces and Russian-backed separatists under a more effective ceasefire and a pull-back of weapons by the two sides from the conflict zone.

Non-allied Finland shares an 833 mile (1,340 km) border with Russia and it was alarmed by several violations of its air space by Russia planes at the height of the Ukraine crisis last year.

Finland's centre-right coalition, which took office in May, has pushed forward with plans to step up defence cooperation with Sweden and is keeping the door open to possible membership of NATO in the future.

Niinisto, who has some power in foreign and defence policy but otherwise holds a largely ceremonial post, declined to comment on NATO membership.

Finland is struggling to handle the influx of asylum seekers as thousands of Iraqi refugees, mostly young men, have surprised authorities by taking the long journey through Central Europe and Sweden to northern Finland.

The government has lifted its estimate for the number of asylum seekers expected to reach the country this year to about 50,000.

"At the moment, the daily pace is proportionally faster than in Germany," Niinisto said.