By Elizabeth Barber

BOSTON (Reuters) - The Boston Marathon course will be a "no-drone zone" this year, Massachusetts authorities said on Monday as they outlined security plans for the race that was the target of a deadly bombing attack two years ago.

In addition to planning to search large bags and coolers, state officials said they would prohibit the use of small aircraft, popular with hobbyists and the tech-savvy, along the race's 26.2-mile (42 km) course, which extends from the suburb of Hopkinton to downtown Boston on April 20.

"We're just trying to encourage people - look, don't create problems by flying these things," said Massachusetts State Police Colonel Timothy Alben.

Some 1 million spectators and about 30,000 runners will flock to the Boston Marathon next week, two years after a pair of pressure cooker bombs exploded at its finish line and prompted authorities to overhaul plans to protect the marathon’s course through eight Massachusetts cities and towns. 

"We are again confident that the security measures in place will not interfere with the event," said Kurt Schwartz, Massachusetts undersecretary for homeland security and emergency management.

Some of the marathon’s security measures will be in plain sight. Spectators and runners should expect to regularly see police officers and National Guard troops during the event, held on Patriots' Day, a Massachusetts holiday celebrating American Revolutionary War battles.

Other security measures will be less visible, including increased numbers of plainclothes police officers and security cameras.

Dzhokhar Tsarnaev, 21, was found guilty on Wednesday of the putting two homemade bombs at the 2013 Boston Marathon, killing three people and injuring 264 others. Prosecutors are expected to begin presenting their case that he should be sentenced to death on April 21, the day after this year's marathon. His brother, Tamerlan, who was believed to have set the bombs with him, died after a police shootout a few days after the bombing.

State police officers are undergoing new training after a recent report found that officers self-deployed to the scene of a Watertown shootout with Tsarnaev and his older brother, Alben said.

In doing so, law enforcement created "dangerous crossfire situations,” the report found.

(Editing by Scott Malone and Bill Trott)