India, May 1 -- As summer vacation approaches, the US has issued a 'Do Not Travel' warning for as many as 21 countries. These include Russia, Ukraine, Iran, and even Iraq. The State Department has four levels of advisories, with 'Do Not Travel' the most serious. Some of the advisories have been issued for months, while others are fairly recent.

This applies to safe tourist spots like Japan, Bermuda, and the Cayman Islands, urging travelers to stay vigilant despite no specific threats.

Travelers should be wary in countries like Saudi Arabia, China, and Spain, where risks include crime, civil unrest, or potential terrorism, but travel is still feasible with caution.

This warning covers 23 countries, such as Chad, Niger, Egypt, Jamaica, a...