Israel has approached the United States for more bombs and asked Washington to increase an emergency arms cache stowed on Israeli soil by 50 per cent, according to the leading newspaper Ha'aretz.

Israel's Defence Minister Ehud Barak made a move for the weapons during a recent visit to Washington

The approach, made by Defence Minister Ehud Barak during a recent visit to Washington, reflects the heightened tensions in recent months between the Jewish state and its neighbours that have given rise to widespread fears within Israel of an imminent regional conflict.

News of the request emerged as members of the international community stepped up the pressure yesterday for a thorough and impartial probe of last week's Israeli raid of a Turkish vessel bound for Gaza with humanitarian aid that ended in a bloodbath.

The Russian Prime Minister, Vladimir Putin, who was attending a regional security summit in Turkey, added to the criticism of Israel and said he would raise the question of who would conduct an inquiry with the United Nations.

Israel has agreed to carry out an investigation, which could be overseen by two international observers, but would be limited to a theoretical debate of the merits of the raid and the blockade. The commandos who led the raid would not be questioned.

Israel has defended its land and sea blockade of Gaza, arguing that it prevents the flow of weapons to Hamas, the Islamist group that governs the strip. Critics say it constitutes collective punishment that has led to a humanitarian crisis.

Fearing that its enemies are rearming along its borders, Jerusalem has asked Washington to increase the emergency stores by $400m (£278m) to $1.2bn and is also seeking to buy more Joint Direct Attack Munition (JDAM) bombs from the US, the liberal newspaper Ha'aretz reported, citing unnamed sources.

The JDAM is a sophisticated satellite-guided bomb used extensively by Israel in the Lebanon War in 2006 and in its Gaza offensive at the end of 2008.

The Israeli Ministry of Defence refused to comment on the report and the US State Department did not respond to requests for comment.

Washington agreed in December to double stores to $800m worth of arms, including rockets, bombs and armoured vehicles, allowing the Israeli forces to use the equipment with US approval in the case of an emergency.

Israel has already done so in the past, falling back on the US munitions during the Lebanon War in which at least 1,200 Lebanese and 160 Israelis were killed.

The Israeli move reflects the country's growing sense of embattlement in a region largely hostile to it. Iran

has repeatedly threatened to erase Israel from the map, while Hizbollah, the Iranian-backed Lebanese militia group, has amassed thousands of rockets along Israel's northern border. Relations with Turkey, once Israel's closest ally in the region, have plunged to new lows following the flotilla raid.

"Israel does have a sense of the coalescing of an alliance which is committed sooner or later to war with Israel," said Jonathan Spyer, senior researcher at the Global Research in International Affairs Centre in Herzliya. "Everyone is building up frightening amounts of military hardware."

Israel recently accused Syria of providing Hizbollah with Scud missiles, a powerful weapon capable of hitting cities deep inside Israel. Syria vehemently denied the claims, countering that Israel was seeking a pretext for war.

Neither Hizbollah, still smarting from the previous conflict four years ago, nor Israel are likely to want another war, Spyer said. Any conflict with Hizbollah would likely spin out of control beyond Lebanon to include Syria and Iran.

The US, Israel's staunchest ally, provided $2.5bn in military aid to Israel last year, freeing up an equivalent amount for spending in other areas. It recently agreed to help fund the country's Iron Dome project, a controversial anti-missile system.

The Independent (UK)