Sequence tag not validated

I have sequence tag in the my schema xsd

<xs:sequence minOccurs="0" maxOccurs="unbounded">
<xs:element name="searchcriteria" type="xs:string" nillable="false"/>
<xs:element name="searchvalue" type="xs:string" nillable="false"/>
</xs:sequence>

if I do xmlobject creation and after I do parsing and validation of a xml that has more elements in the sequence:

<searchcriteria>profileTypeID</searchcriteria>
<searchvalue>5</searchvalue>
<searchcriteria>entityTypeID</searchcriteria>
<searchvalue>2</searchvalue>
<searchcriteria>entityID</searchcriteria>
<searchvalue>1</searchvalue>

xmlInputDoc.validate() returns false, not valid

instead if there is only an element in the xml:
<searchcriteria>profileTypeID</searchcriteria>
<searchvalue>5</searchvalue>

it is valid