Pakistan has been hit by a wave of Islamist militant attacks over the past three years, which many attribute to Islamabad's alliance with Washington and the US-led war against the Taliban in neighbouring Afghanistan.

The blasts hit exactly at the time of breaking of fast in the ongoing holy month of Ramadan.

"Eighteen people were killed and 143 others wounded in the three suicide attacks," a senior local administration official, Sajjad Bhutta, told AFP.

"We have collected bodies of all the three bombers," he said, adding that we are collecting more evidence from the site.

Top local administration official Khusro Pervez told reporters in Lahore that more than 100 people were wounded.

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"The first blast took place immediately after the mourning procession ended followed by other two," Mr Pervez said.

He said that the police was trying to secure other areas, as the mourners are currently scattered everywhere in the area known as Karbala Gamey Shah, the traditional route where the mourning procession ends.

It is not the first time Lahore has seen violence directed towards religious groups.

In July, twin suicide attacks on an Islamic shrine in Lahore, capital of Punjab province and a major military, political and cultural hub, killed 43 people.

The two suicide bombers blew themselves up among crowds of worshippers at the shrine to Sufi saint Data Ganj Bakhsh.

In May, gunmen wearing suicide vests storm two mosques belonging to the minority Ahmadi sect in Lahore, killing at least 82 people.

The United States last year approved a five-year $US7.5 billion ($A8.43 billion) package aimed at reducing the appeal of extremists in the Islamic world's only declared nuclear power by building infrastructure, schools and democratic institutions.

But the United States remains wildly unpopular with the Pakistani public, enflamed by a covert US drone war against Islamist targets in lawless tribal on the Afghan border that Washington considers the global bastion of Al-Qaeda.

There were no immediate claims for the latest attack, which came as the United States added the Pakistani Taliban to a blacklist of foreign terrorist organisations, which means members face asset freezes and travel bans.

US Secretary of State Hillary Clinton designated the Tehreek-e-Taliban as a foreign terrorist organisation on August 12, and it was formally added to the list when it was published Wednesday in the Federal Register.

"I conclude that there is a sufficient factual basis to find that the relevant circumstances described in section 219 of the Immigration and Nationality Act... exist with respect" to the group, she wrote.

"Therefore, I hereby designate the aforementioned organisation and its aliases as a foreign terrorist organisation pursuant to section 219 of the INA," she wrote according to an email distributed by the State Department.

Pakistan is currently battling devastating flooding that has left confirmed 1,760 people dead and more than 2,000 injured, but officials warn that millions are at risk from food shortages and disease.