A bipartisan group of US senators are negotiating a deal on immigration reform in Washington DC, amid rallies in the capital Washington DC in support of the millions of illegal immigrants in the country.

Wednesday's rally, organised by Hispanic and pro-immigration reform groups, took place outside Congress as the reform could contain a long-term path to citizenship for the 11 million illegal immigrants.

The reform, a crucial focus of President Barack Obama's second term, could also entail an expansion of quotas of foreign workers and tighter border security.

"We are optimistic that we will be able to introduce legislation soon," a Senate aide has said on condition of anonymity.

The four Democrats and four Republicans, who have held negotiations since February, could introduce their measure as early as Thursday or in the coming week, according to the AFP news agency.

Comprehensive internal debate is one of the conditions requested by some congressional Republicans, whose party dominates the House of Representatives.

Path to citizenship

In the House, another bipartisan immigration reform bill is being debated amid public sentiment that, according to opinion polls, appears increasingly keen on seeing a comprehensive solution on the matter.

Al Jazeera's Alan Fisher, reporting from Washington DC, said that the reason for the ongoing protests is to "make sure that they don't forget that many of the people, who are in the country illegally, want a path to citizenship".

He said some of the ideas for reform that are being discussed are increased security at the border, proficiency in English, and criminal records, among others.

The last major immigration reform dates back to 1986 when, with Ronald Reagan in the White House, almost 3.5 million illegal immigrants were granted amnesty.

Employers and unions are carrying out parallel negotiations to expand and overhaul entry quotas for workers in all sectors while lawmakers and the government debate border security.

The US deports about 400,000 undocumented immigrants annually.