The blasts, on Thursday, killed 33 people and injured hundreds.
"We've been experiencing terrorism for 30 years," said Samira Murr, a Lebanese teacher in her 50s, in Beirut. "It's like the Madrid bombings, like the 9/11 attacks. We feel we are not safe anywhere in the world any more."
Palestinian negotiator Saeb Erikat said: "We condemn with the strongest possible terms these explosions, and convey our sincere condolences to the British people and government."
Gulf states condemn
Gulf Arab states condemned what they called the "criminal and terrorist" explosions.
Saudi Arabia, itself hit by a wave of attacks by suspected al-Qaida insurgents in the past two years, "strongly condemns" the blasts, said an official source.
Gulf states called the attacks
criminal and terrorist acts
Riyadh "reiterates that ... the international community must step up efforts to combat the terrorism scourge, which now threatens our security," the source said.
In the United Arab Emirates, Deputy Prime Minister and State Minister for Foreign Affairs Shaikh Hamdan bin Zayed al-Nahayan said his country "condemns in the strongest possible terms these horrific crimes and declares full solidarity with the British government".
He said Abu Dhabi also "supports any measures (the British government) may take to deal with" the attacks, which were claimed by a previously unknown group linked to the al-Qaida network, the state news agency WAM reported.
Kuwait denounced the attacks in a letter to British Prime Minister Tony Blair from Prime Minister Shaikh Sabah al-Ahmad al-Sabah, who is currently in the United States.
Shaikh Sabah expressed Kuwait's "strong condemnation" of the blasts that left a number of "innocent casualties," said the state news agency KUNA.
"These terrorist attacks which target innocent lives are against all human norms and values," the Kuwaiti leader said. Shaikh Sabah also expressed "Kuwait's sympathy and support to friendly Britain and to all actions it will take to eradicate vicious terror in order to preserve security and stability."
"These terrorist attacks which target innocent lives are against all human norms and values"
Kuwaiti prime minister
A source at the Qatar Foreign Ministry similarly condemned the "criminal explosions ... which are terrorist acts that flout human and moral values," said Qatar News Agency (QNA).
"The state of Qatar denounces terrorism of whatever kind and whatever its source," the statement further said.
"Qatar expresses solidarity with the friendly United Kingdom and presents its condolences to the families of the victims and the injured," it added.
The Riyadh-based Gulf Cooperation Council (GCC) said in a statement that the club of six oil-rich Gulf monarchies "condemns the terrorist attacks which hit the British capital in several locations this morning".
Qatar's leaders said terrorist acts
flout human and moral values
The bloc, grouping Bahrain, Kuwait, Oman, Qatar, Saudi Arabia and the UAE, "supports all measures taken by the British government to preserve its security and stability," Secretary-General Abdulrahman al-Attiyah said.
The Palestinian Islamist resistance group Hamas condemned the London bombings.
"Targeting civilians in their transport means and lives is denounced and rejected," Moussa Abu Marzouk, deputy chief of the group's political bureau, said.
Leading Lebanese Shia Muslim scholar, Mohammad Hussein Fadlallah, voiced outrage. "These crimes are not accepted by any religion. It is a barbarism wholly rejected by Islam," he said.
"Targeting civilians in their transport means and lives is denounced and rejected"
Moussa Abu Marzouk,
Saudi Arabia's Social Affairs Minister Abdulmohsen al-Akkas said his country knew what London was suffering.
"We understand. Since May 2003, we have been experiencing the horrors of terrorist acts," said al-Akkas, who was visiting London.
"Whoever did it, whether al-Qaida or the animal liberation front, they are animals," said Khaled al-Maeena, editor of Saudi Arabia's English-language Arab News daily.
Lebanon, where a series of bomb blasts this year sparked memories of its bloody civil war, expressed sympathy.
"Lebanon, which has been the victim of violence for years, shares with the British their pain," said President Emile Lahoud.
Some Beirut television stations interrupted their morning shows on cooking and hairdressing to air live footage of bomb sites, casualties covered in blood and rescue operations.
Lebanese president (L) recalled
years of violence in his country
Al-Manar television, owned by the Shia group Hizb Allah, which Washington brands as terrorist, also carried live coverage and news bulletins with the rising casualty toll.
Egypt's Foreign Trade and Industry Minister Rachid Mohamed Rachid, who lived in London until his appointment last year, condemned the attacks while at a conference in Brussels.
"Everyone is following what's happening in London with great anxiety. It is important to be brave in facing up to the scourge of terrorism," the state news agency MENA quoted him as saying.
Morocco, hit by bombings in Casablanca two years ago, expressed sympathy. "These heinous attacks underline the need for the international community to ... unite its efforts to fight these acts and abort their objectives," said government spokesman and Communication Minister Nabil Benabdallah.
The Director of the Institute of Islamic Thought in London, Dr Azam al-Tamimi, while condemning the bombings as barbaric, took the opportunity to criticise leader Blair.
"If there is some party that should be held accountable for killing the innocent and spreading terror and chaos among the British people, it should be the government of Tony Blair," al-Tamimi told Aljazeera.
Some blamed the British leader's
policies for the blasts
He said it was a combination of what the British prime minister and his government had done that led to this disaster.
Britain's role in Iraq and Afghanistan, the abuse of Muslim detainees by British soldiers in Belmarsh prison in London and Guantanamo Bay in Cuba, and even the latest utterances of Blair on his return from Singapore after winning the bid for 2012 Olympics, against "extremists", which al-Tamimi said was a veiled reference to Muslim organisations, all contributed to the blasts.
"This blow was expected any time," al-Tamimi said.