Syria threatens to close borders over planned deployment of U.N. troops

~ Disputes by neighboring countries, gunfire endanger cease-fire agreement.

BEIRUT, Lebanon -- Syria on Wednesday opposed deployment of an international force along its border to prevent arms shipments to Hezbollah, and Israel called the situation in Lebanon "explosive." A cease-fire was further shaken by artillery shells and explosions that killed three Lebanese soldiers and an Israeli.

Lebanese Prime Minister Fuad Saniora asked the United States to help lift an Israeli blockade on his country's coast and airport -- something Israeli Prime Minister Ehud Olmert said would not happen until U.N. troops deployed along the Lebanon-Syria border to block the flow of weapons. Hezbollah's vast arsenal of rockets and other weapons, much of which is believed to originate in Iran, reaches the guerrillas across the Syrian border.

European Union ambassadors and deputies met in Brussels, Belgium, to drum up volunteers for the force, but tentative pledges reached just 4,200 troops by Wednesday -- far short of the 15,000 called for by the U.N. cease-fire resolution. Deployment will likely take weeks or months.

Meanwhile, Syria indicated it might impose a blockade of its own.

"They will close their borders for all traffic in the event that U.N. troops are deployed along the Lebanon-Syria border," Finland's foreign minister Erkki Tuomioja said after meeting his Syrian counterpart, Walid Moallem, in Helsinki. Finland holds the rotating presidency of the European Union.

Lebanon has land borders only with Syria and Israel.

Syria's threat to close its border and Israel's resolve to continue the blockade were among the burgeoning hurdles facing Lebanon as it struggled to meet key requirements of the U.N. resolution: deployment of 15,000 Lebanese soldiers south for the first time in four decades and stiffening control on all borders.

Several incidents erupted along the Israel-Lebanon border Wednesday, with the killing of three Lebanese and one Israeli soldier by exploding ordnance, the capture of two Lebanese men in an army raid, and the resumption of sporadic shelling by Israeli forces in the disputed Chebaa Farms.

Olmert told Secretary of State Condoleezza Rice by phone that the international force must arrive as soon as possible, so the sea and air blockade could be called off, his office said.

Syria -- a Hezbollah benefactor largely left out of diplomacy during the 34-day war -- appeared to insert itself Wednesday.

Syrian President Bashar Assad called any deployment of multinational troops along his border a "hostile" affront to Syria.

"First, this means creating hostile conditions between Syria and Lebanon," Assad told Dubai Television in an interview aired Wednesday. "Second, it is a hostile move toward Syria and naturally it will create problems."

The Aug. 11 U.N. resolution that halted fighting three days later called for the international reinforcements to arrive in Lebanon, but some have complained the mandate was fuzzy.

The additional peacekeepers were to augment the 2,000-strong U.N. Interim Force in Lebanon, known as UNIFIL, deploy south of the Litani River, 18 miles from the Israeli border, and open fire only in defense of themselves and civilians.

"The Israelis cannot ask UNIFIL to disarm Hezbollah. This is not written in our mandate," French Maj. Gen. Alain Pellegrini, the UNIFIL commander, told reporters at force headquarters in Naqoura, Lebanon..

Pellegrini said the cease-fire "is tense, very fragile, very volatile... Any provocation or misunderstanding could escalate very, very rapidly."

Many countries appeared wary of joining without safeguards to ensure they don't get sucked into a new Mideast conflict.

France currently leads UNIFIL but disappointed the U.N. by pledging only to double its 200-strong contingent. French Prime Minister Dominique de Villepin said Wednesday his country wanted "to go further once the conditions are right."

Greek Foreign Minister Dora Bakoyannis visited Beirut on Wednesday and pledged two teams of troops but did not mention numbers.

Saniora accepted a $230 million aid package from the United States and asked Washington to use its influence with Israel.

"The United States can support us in putting real pressure on Israel to lift the siege," Saniora said. Israel imposed a sea, land and air blockade on Lebanon early in the war. Saniora has called its continuation a violation of the cease-fire and reportedly asked Rice and Egyptian President Hosni Mubarak to intervene.

Artillery soared Wednesday in the disputed Chebaa Farms area -- where Lebanon, Syria and Israel meet. Israel said it fired only into its own territory as deterrence. But Lebanese security officials said Israeli troops stationed in the area fired across the border into Lebanon, hitting near Lebanese army positions. Lebanese and Israeli officials agreed no artillery from Lebanon hit Israel.

The Israeli army seized two Lebanese men in a village farther along the border, Lebanese officials said, but Israel did not comment on the claim.

Three Lebanese soldiers were killed as they dismantled an unexploded missile near the southern village of Tibnine, and an Israeli soldier died near Blida when his tank hit a land mine.

Another Israeli soldier was shot in the head the border village of Taibeh, Arab media said, but Israel denied such an incident.

A Lebanese army communique said four Israeli jets flew over huge swaths of Lebanon, including the capital. Such flyovers have been frequent since the cease-fire.

Witnesses in south Lebanon said an Israeli bulldozer and two tanks set up a roadblock and cut off traffic between two Lebanese villages, isolating the town of Bint Jbail.

Hundreds of Israeli troops have remained in the positions they occupied during the fighting, waiting for the U.N. peacekeepers to establish a buffer zone between Israel and Hezbollah guerrillas.