"The United States is deeply concerned that Lashkar-e-Tayyiba (LeT) leader Hafiz Seed has been released from house arrest in Pakistan", State Department spokesperson Heather Nauert said in a statement on Friday.
"LeT is a designated Foreign Terrorist Organisation responsible for the death of hundreds of innocent civilians in terrorist attacks, including a number of American citizens", the statement said, noting: "LeT and several of its front organisations, leaders, and operatives remain under both State Department and Treasury Department sanctions".
Saeed has repeatedly denied involvement in the 2008 Mumbai violence in which 10 gunmen attacked targets in India's largest city, including two luxury hotels, a Jewish centre and a railway station.
United States administration has expressed "deep concern" on the release of designated terrorist: Lashkar-e-Taiba chief and founder of Jamaat-ud-Dawah Hafiz Saeed by Pakistani authorities and asked Islamabad to ensure his re-arrest and slap charge for his crimes.
Mumbai mastermind and Jamaat-ud-Dawah (JuD) chief Hafiz Saeed has been released from house arrest in Lahore.
Saeed was set free from house arrest after the Pakistan government rejected to extend his arrest in any case.
"If Pakistan does not take action to lawfully detain Saeed and charge him for his crimes, its inaction will have repercussions for bilateral relations and for Pakistan's global reputation", it added.
Saeed says again that the USA, on India's request, pressured Pakistan to keep in custody him.
Saeed was speaking to huge of JuD activists at the Jamia Masjid Al-Qadisa at Chauburji after releasing.
Lashkar-e-Tayyiba was behind the 2008 terrorist attacks in Mumbai, India that left 168 people dead, and Saeed is designated as a terrorist by the us government. We've given them billions and billions of dollars, and what did we get?
The US, since 2012, had announced $ 10 million for information that brings Saeed to justice.
"Ousted Prime Minister Nawaz Sharif has been punished for neglecting Kashmiris".
Saeed blamed India for his incarceration in Pakistan, saying "Pakistan's rulers detained me on the aspiration of Modi due to their friendship with him".
Saeed's detention in Lahore since January was initially interpreted as an attempt to placate the United States, which has taken a tougher tone on Pakistan under Trump. "India has always leveled allegations of terrorism...but (Lahore) High Court decision has proved that all of India's propaganda are false", Saeed said.
For years, the Pakistanis have been blamed by the US for not doing enough in their counterterrorism efforts to end the Afghan war - the longest military engagement in America's history.