The remarks by Moussa Abu Marzouk, deputy head of Hamas' political bureau, came as fighting renewed between Hamas and Fatah in Gaza early Wednesday when Hamas gunmen stormed the home of a top Fatah official in Gaza City, killing five bodyguards inside, Palestinian security officials said.
The attack comes after a brutal day of factional fighting between Hamas and Fatah rivals in Gaza that killed 15 people. Four days of intense Palestinian infighting in Gaza have killed 41 people.
"The international community and Arab countries shoulder part of the responsibility for the current events due to their attitudes toward the national unity government," Abu Marzouk said in Damascus.
"The continued financial and political siege has pushed matters to this simmering tension," he said. He also blamed Israel and Arab apathy toward the economic sanctions for the fighting.
"The Israelis are behind all these events," Abu Marzouk said. "It's illogical that the Arabs stand idle watching the Palestinian arena while it's on the verge of explosion under the siege...this is a constant pressure that has led to a real explosion."
Abu Marzouk singled out Javier Solana, the European Union's foreign policy chief, for criticism.
"He was one of the main instigator for these events because he is continuing his seige of the Palestinian people and had boycotted Palestinian elections," the Hamas official said.
After talks in Brussels Tuesday with Palestinian Foreign Minister Ziad Abu Amr, Solana rejected criticism that the inter-Palestinian fighting was due to the international aid embargo the EU and other key donors including the US and the UN have imposed on the Palestinian government.
The major donors have demanded Hamas - a majority member of the unity government - recognize Israel, renounce violence and commit to past agreements before aid is restored. Hamas has rejected the demand.
Abu Marzouk ruled out the possibility of a Palestinian civil war. "This is absolutely rejected by all Palestinian parties," he said.
This week's fighting between Hamas and Fatah was the worst since the two groups agreed in February to share power in a national unity government.