Two ethnically-Chechen brothers suspected of carrying out the Boston Marathon bombings had no connection with Chechnya, the leader of the mainly Muslim region in southern Russia said Friday, blaming their upbringing in the United States.

"They grew up in America, their views and convictions were formed there. The roots of evil must be sought in America," the strongman leader of the North Caucasus republic, Ramzan Kadyrov, wrote on his Instagram account.

Hizbullah deputy chief Sheikh Naim Qassem stressed on Friday that the Lebanese people can handle their own affairs without political directions from any power.

He said addressing U.S. Ambassador to Lebanon Maura Connelly: “We do not need your advice over the parliamentary elections or any other issue.”

Mortars and a bombing north of Baghdad killed eight people on Friday, on the eve of Iraq's first polls since U.S. troops withdrew and a day after a blast in a cafe in the capital left 27 dead.

Four mortars struck the Abu Tamur mosque in the town of Khales, which lies in restive Diyala province, as worshippers were departing following mid-day Friday prayers, a police colonel and a doctor said.

The two suspects in the Boston Marathon bombing killed a university police officer and hurled explosives at police in a car chase and gun battle overnight that left one of them dead and his brother on the loose, authorities said Friday as thousands of officers swarmed the streets in a manhunt that all but paralyzed the Boston area.

The suspects were identified by law enforcement officials and a family member as Dzhokhar and Tamerlan Tsarnaev, brothers from a Russian region near Chechnya, which has been plagued by an Islamic insurgency that has carried out deadly bombings.

A 45-year-old man suspected of sending poison-laced letters to President Barack Obama and a U.S. senator has been charged with threatening the life of the president, authorities said Thursday.

Paul Kevin Curtis was arrested Wednesday by the FBI at his home in Corinth, Mississippi, and was due to appear in court Thursday. If convicted, he faces up to 15 years in prison and $50,000 in fines, prosecutors said.

A suspicious substance was found at a U.S. naval building near Washington, the Pentagon said Thursday, after authorities earlier discovered two letters laced with deadly ricin sent to President Barack Obama and a U.S. senator.

"A suspicious substance was found in the mailroom of Building #12 at Naval Support Facility" in Arlington, Virginia, just outside the U.S. capital, and all personnel were evacuated from the building as "a precaution," the statement said.

A suspected U.S. drone strike in western Yemen has killed five al-Qaida militants, including a local chief, a security official and witnesses said on Thursday.

The raid that took place late Wednesday in Dhamar province, killed Hamid Radman al-Manea, known as al-Radmi, and four of his guards, the official said in a statement carried by Saba state news agency.

A Mississippi man was arrested Wednesday, accused of sending letters to President Barack Obama and a senator that tested positive for poisonous ricin and set the nation's capital on edge a day after the Boston Marathon bombings.

Paul Kevin Curtis, 45, was arrested at his apartment near the Tennessee state line east of Memphis, said FBI Special Agent in Charge Daniel McMullen. It wasn't immediately known where he was being held.

The United States plans to deploy 200 troops in Jordan because of "the deteriorating situation" in war-torn Syria, Information Minister Mohammad Momani said on Wednesday.

"The deployment of the troops is part of U.S.-Jordanian military cooperation to boost the Jordanian armed forces in light of the deteriorating situation in Syria," Momani told Agence France Presse.

U.S. Ambassador to Lebanon Maura Connelly on Wednesday voiced concern that delaying the parliamentary elections could aggravate the tensions in Lebanon and affect economic investments.

In an interview on Future TV, Connelly revealed that her administration had a problem in dealing with the outgoing cabinet of caretaker Prime Minister Najib Miqati due to Hizbullah's presence in the government.