French Foreign Minister Philippe Douste-Blazy called Israel's bombardment of Beirut airport ''a disproportionate act of war'', adding the risk of a regional war ''absolutely'' existed.
Russian Foreign Ministry Spokesman Mikhail Kamynin denounced both Israel's attack on Lebanon and its on-going operations against the Palestinian territories.
''The continuing destruction by Israel of civilian infrastructure in Lebanon and in Palestinian territory (and) the disproportionate use of force from which civilian populations suffer cannot be understood and justified,'' he said.
''The attack on Beirut international airport is a dangerous step on the way to military escalation,'' he added, calling on all sides to stop a slip towards war.
Israel struck Beirut airport and began enforcing a naval blockade of Lebanon today, intensifying reprisals after Hizbollah seized two Israeli soldiers and killed eight in cross-border attacks a day earlier.
Douste-Blazy said: ''For several hours, there has been a bombardment of an airport of an entirely sovereign country, a friend of France ... this is a disproportionate act of war.'' Douste-Blazy also condemned Hizbollah's firing of rockets into northern Israel and the kidnapping of the soldiers, telling Europe 1 radio these were ''irresponsible acts''.
''The only solution is a return to reason by both sides,'' he said. ''We are calling for a lowering of tensions,'' he said.
The Israeli attacks have killed 36 Lebanese civilians.
Hizbollah fired barrages of rockets into towns across northern Israel on Thursday, killing one civilian and wounding 29 others in their heaviest bombardment in a decade.
The violence was the worst between Israel and Lebanon since 1996 when Israeli troops still occupied part of the south. It coincided with a major Israeli offensive into the Gaza Strip to retrieve a captured soldier and halt Palestinian rocket fire.
The United States held back from criticising Israel but called for a lowering of tensions.
''We are urging restraint on both sides, recognising Israel's right to defend itself,'' a US administration official said, speaking on condition of anonymity.
The US official reiterated the White House's blame of Syria and Iran for the Hizbollah attacks on Israeli soldiers.
''The Syrians and the Iranians bear some responsibility by virtue of their harbouring Hizbollah,'' the official said.
President George W. Bush, who is travelling in Germany for meetings with Chancellor Angela Merkel, was expected to discuss the Lebanon situation at a news conference later today.
Spain demanded a release of the kidnapped soldiers and ''an end to armed aggression against Israel''.
''We also ask Israel to act with moderation, in proportion to what has happened, keeping in mind how important it is not to allow the violence to spread, which would endanger the stability of the region with civilians, once again, the main victim,'' the Spanish foreign ministry said in a statement.
REUTERS SHB KN1640