Secretary of State Mike Pompeo has said the US is imposing the "strongest sanctions in history" on Iran.

In a speech in Washington, America's top diplomat said Iran would be "battling to keep its economy alive" after the sanctions took effect.

He said he would work closely with the Pentagon and regional allies "to deter any Iranian aggression".

All 34 Chilean bishops who attended a crisis meeting this week with Pope Francis about the cover-up of sexual abuse in their country have offered to resign, the bishops said in a statement released on Friday. It was not immediately clear if the pope would accept all or any of the resignations.

Births in the US have dropped to their lowest rate in 30 years, marking a cultural shift as women delay motherhood, experts say.

Some 3.85 million babies were born in the US in 2017, the fewest since 1987, as births among women in their teens and 20s decreased.

Both the birth rate - the number of births per thousand - and fertility - a lifetime average forecast - fell.

President Nicolas Maduro was declared the winner of Venezuela’s election Sunday in a poll rejected as invalid by his rivals, who called for fresh elections to be held later this year. With more than 90 percent of the votes counted, Maduro had 67.7 percent of the vote, with his main rival Henri Falcon taking 21.2 percent, the National Election Council chief Tibisay Lucena announced.

Multiple people were killed on Friday in a shooting at a high school in Santa Fe, Texas, CNN reported, in the latest gun violence in a country still shaken by the massacre at a Florida high school in February. According to some media reports the suspect is in custody. Citing unnamed sources, CNN said there were multiple fatalities after the shooting at the school about 30 miles (48 km) southeast of Houston.

Two U.S Air Force stealth fighter jets intercepted two Russian nuclear-capable bombers Friday in international airspace off the coast of Alaska.

The approach by the two Tupolev Tu-95 Russian "Bear" aircraft marked the first time in just over a year that Russian bombers had flown that close to U.S. territory, bearing about 200 miles off Alaska’s west coast, about 10 a.m. EST (1400 GMT), North American Aerospace Defense (NORAD) Command spokesman Canadian Army Major Andrew Hennessy said in a statement to CNN.