Two emperor tamarin monkeys have gone missing at a zoo in Texas, the latest in a string of bizarre animal incidents to rock the Dallas Zoo.

Zoo authorities called the local police "after the animal care team discovered two of our emperor tamarin monkeys were missing," the zoo tweeted late yesterday.

In a separate statement, Dallas police said a cut was made to the monkey habitat "and it is believed the animals were intentionally taken from the enclosure".

It marked the second time animals have vanished from the facility in recent weeks. The zoo closed on 13 January after keepers discovered a breach in the enclosure of a clouded leopard.

The missing big cat was eventually found near her habitat and had not left the zoo grounds.

A little more than a week later, the zoo reported that an endangered lappet-faced vulture was found dead from a "wound," and the "circumstances of the death are unusual".

In the latest incident, the zoo said employees searched near the monkey habitat and across zoo grounds but did not find the emperor tamarins, which "would likely stay close to home".

"Based on the Dallas Police Department's initial assessment, they have reason to believe the tamarins were taken," the zoo statement said.

"This is an active Dallas Police Department investigation. This is all the information we are able to share at this time."

After the vulture was found dead, the zoo - the oldest and largest in Texas - said it "added additional cameras throughout the zoo and increased onsite security patrols during the overnight hours".

The emperor tamarins are small monkeys with long white whiskers that sweep back from their faces, and are so named for their likeness to the late German emperor Wilhelm II. The monkeys are native to the southwest Amazon basin.

The incidents have raised alarms at zoos across the US, fearful of copycat crimes.

A Louisiana facility, Zoosiana, reported yesterday that 12 squirrel monkeys were stolen from their habitat after intruders broke in over the weekend.