WASHINGTON, Jan 9 ― The FBI is offering a reward of up to US$50,000 (RM201,647) for information on who placed pipe bombs in the committee headquarters of both major US political parties in Washington.

Law enforcement agencies had received reports of two suspected devices, one each at the headquarters of the Republican National Committee and the Democratic National Committee on Wednesday, the FBI said in a statement.

The statement was accompanied by an image of a masked suspect wearing gloves and a hooded sweatshirt, carrying an object.

"The FBI is offering a reward of up to US$50,000 for information leading to the location, arrest and conviction,” it said.

The US Capitol police said the devices could have caused "great harm.”

"The USCP Hazardous Materials Response Team determined that both devices were, in fact, hazardous and could cause great harm to public safety,” police said in an emailed statement.

ABC News reported that bomb technicians used water cannon to blast the devices to break them apart and render them harmless on Wednesday just as supporters of US President Donald Trump stormed into the Capitol building, where lawmakers were certifying the victory of President-elect Joe Biden.

Trump initially praised his supporters but later condemned the violence.

Senators and Congressmen were forced to evacuate after Trump supporters smashed windows and engaged in looting. The violence, which killed five people, followed a rally at which Trump exhorted supporters to fight to overturn the result of the November 3 election that he lost.

House of Representatives Speaker Nancy Pelosi said on Friday that if Trump did not resign, she had instructed the House Rules Committee to move ahead with a motion for impeachment and legislation on the US Constitution's 25th Amendment, which provides for removal of a president who is unable to discharge his official duties. ― Reuters