Amnesty International and Human Rights Watch were among around 30 human rights groups behind the Global Day for Darfur.
The event was organised to coincide with the start of the United Nations General Assembly debate today on Darfur and to mark the first anniversary of the signing of the 2005 UN World Summit Outcome Document.
The document pledged "to take collective action... if national authorities manifestly fail to protect their populations from genocide, war crimes, ethnic cleansing and crimes against humanity," according to the event's organisers.
Demonstrations took place in cities across the globe, stretching from
Bamako to Berlin, Dubai to Dublin, Manama to Melbourne and from Seoul to Stockholm.
The conflict in Darfur between rebels and government-backed Arab militia began in February 2003 and has left more than 300,000 people dead and 2.5 million displaced, according to the United Nations.
The international community, led by the UN and the United States, has called for an embattled contingent of African Union monitors to be replaced by a more robust force of UN peacekeepers.
But the Sudanese government has consistently rejected the option, accusing Washington and the West of seeking to invade the country and plunder its resources.
Madeleine Albright, former US secretary of state, was among the speakers at a demonstration in New York City's Central Park.
In London, a demonstration took place outside the Sudanese embassy followed by a march to the prime minister's residence in Downing Street where senior members of Britain's Christian, Jewish and Muslim faiths held a prayer vigil.
Blair plea to EU
The rally coincided with a letter from Prime Minister Tony Blair to his EU counterparts appealing for heavy pressure on the Sudanese government and rebels to stop the civil war, saying the bloc should play a "central role in mobilising world opinion on this issue".
"We should work to create the broadest possible coalition to speak with one united voice on this issue," Mr Blair wrote.
In Brussels, around 100 people gathered outside the Sudanese embassy.
"Khartoum wants to send its own troops to bring calm to Darfur but how can these troops, which include elements implicated in human rights abuses, bring security and stability?" asked Jan Brocatus of Amnesty International Belgium.
Elsewhere in the EU's symbolic capital, EU Commission President Jose Manuel Durao Barroso said in a statement he would visit Sudan soon.
During his visit he would also travel to the Ethiopian capital Addis Ababa for the first ever meeting with the EU Commission's sister organisation, the Africa Union Commission, on October 2, focusing on Darfur and immigration.
In Paris, French pressure group "Urgence Darfour" (Emergency Darfur) distributed postcards calling on French President Jacques Chirac to "use his influence in the (UN) Security Council for the...immediate sending of blue helmets to Darfur".
Later, French President Jacques Chirac told Europe 1 radio that he would appeal to
Sudanese President Omar al-Beshir to accept UN troops to tackle the Darfur crisis.
"I will make a solemn appeal to the president of Sudan for him to accept the arrival of the UN" to resolve the crisis in Darfur, the French president said.
In Rwanda, however, the government banned a rally in support of sending UN peacekeepers to Darfur, saying it was concerned about the message the event would send as Rwandan troops participated in the beleaguered AU peacekeeping mission in Darfur.
Meanwhile in Sudan, a group of local voluntary organisations marked the day by staging a protest denouncing the worldwide solidarity event as a Jewish conspiracy.
Fathi Khalil, the chairman of the pro-government Sudanese Bar Association, accused Jewish organisations of having "pressured America and Britain to sponsor resolution 1706", which calls for a UN deployment in Darfur.